Issues you'll have is that the low cost models generally use 3 or 4 cell batteries to keep the cost down.
So while they are cheap don't expect to get more than 2.5-3 hours out of them.
Also how's your typeing on a small keyboard?
Have you considerer one of these?
Personally, even if netbooks had exesisted when I was at uni, I'd still write by hand then type them up later.
Granted my typeing skills suck and it's faster and simplier for me to write, but the very act of typeing it up later makes you go through it and helps reinforce it in your mind.