My FirefoxPortable, ThunderbirdPortable, and PidginPortable program folders all fit easily into my Dropbox. I have the Dropbox client installed on my home desktop, home laptop, and office desktop. When I stop using one computer to move to another (like when I come home from work), I make sure to close these programs. By the time I get home, all of the files have synced, so I can now see all the Firefox windows I had left open, all the Thunderbird emails I saved at work are available, and my Pidgin chat logs are there to be searched. This has allowed me to ditch my jump drive altogether!
Caveats: I don’t have the client installed on the Reference Desk computer, since it is a shared computer and that would give everyone access to my files. I also have to remember to close the programs as I change computers, as it will create “conflict” files in Dropbox otherwise. I can tell you from experience, it’s a lot easier to remember to close programs than it is to keep up with a thumb drive!
Give it a try, and let me know if you encounter any other tech tips I might find helpful!