Well I'm a LINUX nut so I think it would be quite a good idea. I have nothing at all against Apples (other than their similar world conquering attitude as MS).

What I think is important for your situation is some sort of after sales service package / warranty / help for if things go wrong. The computer itself is almost irrelevant. That's why I say just get a good screen resolution - everything else will follow suit anyway so don't worry too much about the other stuff...

BUT

What happens if something goes wrong? How much grief will you be getting from your wife if your cheap solution lets her down? Unless cash is really tight I would say that doubling your budget and thus making the problem someone else's (I have a warranty so FIX IT!) might seem like a bit of a bargain if the fit hits the shan...