6 months ago if you were doing music, I'd have said to go with a PC as I could not stand Apple's audio program Logic and I used Adobe Audition all through college. With the latest update, however, Logic is by far my favorite audio application.
Basically it comes down to what you like. If you like windows and don't mind dealing with anti-virus, anti-spyware, anti-whatever software all the time, go with a PC. I personally don't like windows at all and prefer OS X, so I am willing to spend the extra money on Macs. Yes I like the way my powerbook looks more than window-based laptops, but I would never spend the extra money for that. I spent it because I've had two powerbooks in 6 years and have not had a single hardware issue, and the only time they ever froze was a result of a 3rd party program (usually microsoft office). Also because I love Apple's Final Cut Studio for all my video needs.