[Azayzel]

Scratch the eInk devices out now, unless you want to spring $600 for an Iliad, and get an iPod Touch (or iPhone if you need one). It displays PDF's better than any device I've used so far and won't break your bank if you get an 8GB version. PDF's are just terrible on my PRS's and a slate laptop might be too much to carry, though you can see a whole page at once on one... power consumption comes to mind... Easiest way to see for yourself is to load up a PDF to an SD card and stop by some place local where you can take it for a test-drive.

Good luck!

Edit: Forgot about the all important Tablet PC! You can get one on eBay, in my opinion, a slate is best for just PDF viewing; i.e., in class, on-the-go, and stuff; plus, one can be for about the price of a 32GB Touch or less than an Iliad. As always, do your research into the sellers feedback/activity before buying anything of high value on eBay. Be safe!