hi Fur!
I'd go for an Apple. The main reasons are that Windows has had some poor upgrades, which users including professional consultants tell me are very time consuming and troublesome, especially when you are unable to get on with your work.
I believe there are less than 50 viruses for the Mac, but over 100,000 for the PC, which means almost constant upgrades / downloads, which also takes time.
I understand that the basic security on a Mac is tighter, due to its Unix core.
I like to spend my time working, with as little maintenance and troubleshooting as possible, because time is money, also I dislike 'managing' my computer... I want it to work when I need it to and otherwise not have to think about it.
I suggest you look at a Macbook instead of a Pro as they are far more accident proof, less sexy, but better value for money. I've never regretted moving to a Mac about 15 years or more ago.
I'd also consider a rugged external HD and use Time Machine, which is supplied on the laptop to back it up regularly, just to make sure you're covered:
http://www.testfreaks.com/external-hard-drives/freecom-toughdrive-pro-250gb/
What makes a difference to me is all of the above and the fact that photographers hammer their machines day in day out with unusually large files, we need speed and reliability.
Educational discount:
http://store.apple.com/1-800-MY-APPLE/WebObjects/AppleStore.woa?routing=eduind&cid=AOS-US-Edu-EdMkting-01162009 :-)
It's worth asking for a recon model, calling is better than using the website as reconditioned stock moves fast. It will be guaranteed, 'as new' and better value for money... so if you're going to go Mac, now is a good time to do it!
;-)
Happy birthday and good luck!