hay justlisa,
I know that if you're in optometry school at PCO, ALL OF THEIR CLASS NOTES are online so, it would behoove you to get a laptop...as its easy access (but again, only if you live in Penn.)
as far as computers go, i have the Sony laptop (its not really mine, i share it with family) but it doesnt have all the extras like CD burners etc. you can just do email and type papers on it basically
and sinceyou'll be in opt. school, thats all you'll need really.