As usual many of these links were found on digg.com or downloadsquad.com. By the way, I haven’t tried all of the software listed here…

Wikipedia List of portable applications – A list of applications that can be run from portable media; generally a USB “thumb” drive.

Open Source Windows – A list of some of the best Free and Open Source software available for Windows

The 46 Best-ever Freeware Utilities

SmallWindows – Expose-like software for Windows

TimeSnapper – Automatic Screenshot Journal