I used to think the same way. 2 kids off to college, money is tight but I gave them each their choice of laptops:
1.) kid#1 chose a Dell because she <gasp> liked Vista

2.) kid#2 chose the plain old white macbook
3 years later, guess which one is currently crap? Seriously, Kid#1 comes home one day, opens up her Dell and she's got 3 keys missing one of which is the Enter key - has no clue where they went.

Also, the battery is lasting a full 20 minutes and the DVD drive is kaput. The damn thing creaks and moans more than my arthritic joints.
Now, the lowly white macbook looks like it's been used as a door mat (which I polished up for kid #2 in about 5 minutes) but it works flawlessly.
Really... don't rationalize the cost. Kids are tough on these things and you aren't always there to "learn 'em" how to handle them. A well built mac + Applecare is a pretty secure future for their learning experience.