Moving around with your settings
When I bought my first USB flash drive, it was basically for storage of files and photos and mostly as a backup of my web files. Lately storage has sort of taken a back seat although I still use it for that but I now increasingly use my USB flash drive for running portable applications from PortableApps.com.
One of the most useful portable applications that I use is Firefox Portable. This helps me to use Firefox but will all my usual bookmarks and extensions irrespective of what PC I use. This is quite useful for me because my bookmarks contain most of the sites that help me with my work.
I think the second most important application would have to be Thunderbird Portable. Once in a while I use Mail2Web to access my e-mail but while you can read and sent e-mail quite alright you won't have access to your address book and this is where Thunderbird Portable comes handy.
The one portable application but I haven't tried yet but will be trying soon is XAMPP. This is an integrated
server package of Apache, mySQL, PHP and phpMyAdmin that will allow you to do your
development from a USB flash drive and until I try it out I can't say any more.