Super User 
These two wiki questions by Ram and Jonathan Sampson:
1. Best portable apps to keep on a thumbdrive for developers.
2. List of tiny portable free apps that you use
asks the Super User community for their favorites in portable apps. Here’s what you came up with:
PortableApps (answered by nik)
PortableApps is a piece of software that is similiar to PenDrive Linux where all of the portable apps and their setting are taken care of by one single application. There are plenty of Apps that you can choose from, including but not limited to:
There are many, many more apps not listed here so we suggest looking at full list. It’s noteworthy to realize that when you download these apps from PortableApps.com they sometimes will not work as a standalone program, and ONLY with the PortableApps software.
Standalone Portable Apps:
If you decide to manage your portable apps on your own then T Pops and jtimberman both suggested this list of portable “must have” apps that they carry with them all the time:
Filed under Software
Oh Lord, how I love Clamwin! I’ve used it as a last-ditch effort to clean up so many friends’ computers when that sketchy torrents website they frequented finally caught up with them. Making it portable was the best thing they ever did. Anyway, this is a good start, but if you’re looking for a really extensive master list, I found http://etoolsonline.com/my-rig/ very helpful, so maybe you might too. Thanks for the info and keep ’em portable! 😀