I'm a PC person, but when it came to buying a laptop for class (i have an old pc desktop which i'm currently fixing. just gotta order a new motherboard), i made sure to just go w/ one that wouldn't need micromanaging or give me errors a lot, so i went Apple. I have an ibook G4 that i absolutely love. I so wouldn't want a PC laptop, just as I so wouldn't want a Mac desktop.
it's not necessary, but at a lot of med schools it is very beneficial to bring a comp to class or the library. that's why i finally got a laptop (had been refusing to get one for years). And since my desktop has been down for a few months, it's been a life-saver.
But if u honestly can't afford to get one on loans (u can get an educational discount on laptops, BTW), then ur desktop should suffice, though i don't recommend it too much.