As long as they are USB and look like a little stick, they are a flash drive (which is what I call them).
Here's a couple. One is 1GB. The other 2GB. They are both probably the best one's as far as bang-for-your-buck go. The prices have seriously dropped since I last bought one.
But anyways, basically all you have to pay attention to is the Read and Write speeds of it. And then look at the construction of it. Like, is it going to survive if you drop it? Will it fit with a bunch of other cables surrounding the port? Stuff like that.
So, you must choose wisely. (Sorry I've always wanted to say that.)