Check out the F1 series from WD, fast and somewhat affordable if you consider all the space you get. Haven't heard too many good things about WD, but I've never had problems personally.
I meant Samsung F1 Spinpoint drives are supposed to be pretty fast and have a good amount of space for an affordable price.
I you want a WD then go for the Raptors if you don't mind spending that much. They don't have a ton of space but enough for most people, however they have the fastest average speeds.
If you want Seagate just get the .11 drives rather than .10. They seem to be as average as average can be, but with a little more speed.
