UniExtract (Portable)

Universal Extractor is a program do to exactly what it says: extract files from any type of archive, whether it's a simple zip file, an installation program, or even a Windows Installer (.msi) package. 

This application is not intended to be a general purpose archiving program. It will never replace WinRAR, 7-Zip, etc. What it will do is allow you to extract files from virtually any type of archive, regardless of source, compression method, etc.

Its an easy, convenient way to extract files from installation packages, such as Inno Setup or Windows Installer packages, without pulling up a command line every time.

http://www.winpenpack.com/en/download.php?view.1271

Sumatra PDF Reader (Portable)

Sumatra PDF is a slim, free, open-source PDF, DjVu and comic viewer for Windows.

Sumatra has a minimalistic design. Simplicity has a higher priority than a lot of features. It's small and starts up very fast.

http://www.sumatrapdfreader.org/download-free-pdf-viewer.html

Equalizer APO

Equalizer APO is a parametric equalizer for Windows. It is implemented as an Audio Processing Object (APO) for the system effect infrastructure
introduced with Windows Vista.





Features:
- virtually unlimited number of filters (currently limited to 100 per channel for sanity)
- works on any number of channels
- very low latency, which makes it suited for interactive applications
- low cpu usage

Requirements:
- Windows Vista or later (currently only Windows 7, 8 and 8.1 have been tested)
- Sound card driver must support APOs (this includes most onboard sound drivers)
- The application must not bypass the system effect infrastructure
(possible by using special APIs like ASIO)

http://sourceforge.net/projects/equalizerapo/


Update 17. aug. 2014: 
GUI for Equalizer APO i recommend EQ31GUI-2

Get EQ31GUI-2 here: 
http://jiiteepee.tripod.com/eq31gui-2.html

MD5 & SHA Checksum Utility (portable)

MD5 & SHA Checksum Utility is a tool that allows you to verify the integrity of a file by finding out its MD5, SHA-1, SHA-256 and SHA-512 signatures, as the name implies. Its features can be seamlessly handled by inexperienced users.

The interface of the program is quite simple to figure out, as all the options are visible in the main window. So, you can open a file by using either the file browser or "drag and drop" method; the MD5, SHA-1, SHA-256 and SHA-512 checksums are automatically displayed and you can copy either of them or all text to the Clipboard. In addition, you can insert another hash, in order to compare it to the file's.

http://www.softpedia.com/get/Security/Security-Related/MD5-and-SHA-1-Checksum-Utility.shtml

Rufus (portable)

Rufus Portable is a USB formatting utility which also can create a bootable USB drive using a bootable ISO image. 

Rufus is a small utility that helps format and create bootable USB flash drives, such as USB keys/pendrives, memory sticks, etc. It can be be especially useful for cases where: you need to create USB installation media from bootable ISOs (Windows, Linux, etc.); you need to work on a system that doesn't have an OS installed; you need to flash a BIOS or other firmware from DOS; you want to run a low-level utility. Rufus is significantly faster than similar utilities and it's open source and free.

http://portableapps.com/apps/utilities/rufus-portable

HD skins for AIMP3 by Black_AVP

Real HD skins for AIMP3 by Black_AVP. 

Александр Путилин aka Black_AVP is a master of making HD skins. Perhaps the best looking skins ever made to an audio player.


Requirements:
AIMP3: http://portableapps.com/apps/music_video/aimp-portable

Get real HD skins for AIMP3 by Black_AVP here:

http://www.aimp.ru

fre:ac (portable)

fre:ac is a free audio converter and CD ripper with support for various popular formats and encoders. It currently converts between MP3, MP4/M4A, WMA, Ogg Vorbis, FLAC, AAC, WAV and Bonk formats.

With fre:ac you easily rip your audio CDs to MP3 or WMA files for use with your hardware player or convert files that do not play with other audio software. You can even convert whole music libraries retaining the folder and filename structure.

The integrated CD ripper supports the CDDB/freedb online CD database. It will automatically query song information and write it to ID3v2 or other title information tags.

http://portableapps.com/apps/music_video/freac_portable

CDEx (portable)

CDex can extract the data directly (digital) from an Audio CD, which is generally called a CD Ripper or a CDDA utility. The audio can be saved to multiple audio formats and the tracks automatically named using online disc information.





CDEx supports the following features:

• Supports multiple encoders (Lame MP3, Fraunhofer MP3, OGG, FLAC, etc)
• Direct recording of multiple tracks
• Read / store album information from/to a local and/or remote CD Database (CDDB)
• Support CD-Text (if your CD-drive supports it)
• Advanced jitter correction (based on the cd-paranoia ripping library)
• Indicates track progress and jitter control
• Normalization of audio signal
• Supports many CD-Drive from many manufacturers
• Conversion of external WAV files
• Support for M3U and PLS play list files

http://cdexos.sourceforge.net/?q=download

Wise Registry Cleaner (portable)

Wise Registry Cleaner Portable is a registry cleaner and optimizer packaged as a portable app, so you can work on PCs on the go. It's freeware for personal and education use. Like many system utilities, this requires admin privileges to run.

Wise Registry Cleaner includes a fast scanner to check for registry problems. It can backup the registry to ensure it is safe to restore. It has the ability to defragment the registry (note that it will require a reboot so ensure all your apps are closed and it will give a warning about not shutting down properly when run again). The interface is very easy to use for novice users and pros alike.

http://portableapps.com/apps/utilities/wise-registry-cleaner-portable

Wise Disk Cleaner (portable)

Wise Disk Cleaner Portable is a disk cleaner and defragmenter packaged as a portable app, so you can work on PCs on the go. It's freeware for personal and education use. Like many system utilities, this requires admin privileges to run.

Wise Disk Cleaner cleans temporary files, history, cookies and autocomplete form history of Internet Explorer, Chrome, Firefox and Safari browsers. And it removes of Windows junk files, such as Recycle Bin, Recent Documents, Temporary files and Log files. This freeware tool cleans a lot more files than most similar products and includes a "slim down" mode that gets rid of a lot of extraneous objects including wallpapers and other Windows files you may never use. A disk defrag feature is also included for free.

http://portableapps.com/apps/utilities/wise-disk-cleaner-portable

LAV Filters (formerly LAVFSplitter)

LAV Filters (aka LAVFSplitter) is a multi-format media splitter/decoder that uses libavformat (the demuxing library from ffmpeg) to demux all sorts of media files. 

MKV/WebM, AVI, MP4/MOV, MPEG-TS, FLV, OGG are tested and will be registered for.
Other formats can be tested using GraphStudio. H264, VC-1, MPEG4-ASP (Divx/Xvid), VP8 have been tested and are working well. DTS, AC3, TrueHD, MP3, Vorbis have been tested. Subtitle Support. Stream Switching.

http://www.videohelp.com/tools/LAV-Filters

madVR (high quality video renderer)

madVR is a high quality video renderer (GPU assisted) that can be used with any media player which supports madVR; just select madVR as the preferred renderer in the media player's settings.

http://www.free-codecs.com/download/madVR.htm

UnDBX (portable)

Tool to extract, recover and undelete e-mail messages from Outlook Express .DBX files. 

On first run all messages are extracted as individual .EML files. Subsequent runs only update the output directory with new messages, and delete old .EML files that correspond to deleted messages in the .DBX file. Corrupted .DBX files (including files larger than 2GB) can be opened in recovery mode, in order to recover messages and partially undelete deleted messages. The success of recovery depends on the type and level of .DBX file corruption.

http://code.google.com/p/undbx/

McAfee Stinger (portable)

McAfee Stinger removes 6,000 common viruses and 'fake alert' malware on-demand. It is not a replacement for a full antivirus, but handy in many situations. McAfee Stinger is freeware for personal and business use and requires admin rights.

McAfee Stinger detects and removes prevalent Fake Alert malware and threats identified in the "List Viruses" section of the Stinger application. While not a replacement for full fledged antivirus software, Stinger is updated multiple times a week to include detection for newer Fake Alert variants and prevalent viruses.

http://portableapps.com/apps/security/mcafee-stinger-portable

WinMd5Sum (portable)

WinMd5Sum Portable is a simple MD5 sum checker that allows you to check and compare the md5 sums of files. 

What's an MD5 Sum? An MD5 sum is a cryptographic hash used to verify the integrity of files. So, when you download a file, you can check what the publisher says the MD5 sum is and compare it to the MD5 sum of the file you have.

http://portableapps.com/apps/utilities/winmd5sum_portable

More about MD5...