Version of Linux for portable flash drive

For school, I want to use a flash drive that runs linux.  I am sick and tired of logging on to old computer that are not fast enough to run windows 7 well, and then deal with all the different setting on each of the computers.  Then when I go home to my desktop I have to make sure I saved everything on the flash drive that I need every time to go to and from school.  

My question is what linux os would work best on a usb 2.0 flash drive.

Any linux distro will do. If you want the most speed, and don't care much about bling, check out Vector Linux, I would suggest the Gold Edition, because it's small (leaves some space for storage of your documents also on your USB stick next to the linux install), it's fully functional (all most used programs are installed), and it's really fast (minimal slackware based distro), even on older hardware and very little RAM (128MB of RAM is enough).

Manjaro is also a good choice, it's fast (arch based) and modern and fully loaded.

I allways have a copy of puppy on a usb stick (PuppyPrecise) loads in to ram and runs lightning fast.

Yup, also good choice, puppy is also slackware-based, and there is a choice between puppy wary for old slow computers (like 10-15 years old computers and stuff), and puppy racy for reasonably recent (like <10 years old) hardware, which might be handy. Vector linux is basically more stuff than puppy wary with the same very low resource requirements, but if the system can take it, maybe puppy racy is a good alternative, if a modern distro doesn't quite run that well. Lot's of choice.

Thank you for all your input.  I will be trying all of them, but it sounds like vector will be the best choice.