Uh there are a bunch of upgrades for an apple... especially with OSX. You can buy replacement processors for macs. Infact they are not that expensive, same with video cards several companies make Mac cards, Including ATI, NVidia, and Matrox. Creative Labs now makes a sound card for the Mac, and I assume they will have more to come. Now that Apple dropped the built in SCSI thing, they are almost completly compatible with standard PC parts, such as Hard Drives, RAM, and PCI cards. I have two macs and one PC, ever since OSX my iMac and my dual G4 I have not had any crashes at all. I cannot say that about my P4 2.4Ghz runnign XP. I have already had to reinstall XP in the 4 months I have had it, and last month I had to replace the processor as it was dead. I cannot even say the headache I had to go through to get Intel to replace the damn thing, they were trying to get me to buy a new one. Now if you play games and that is your thing a Mac in not for you, in fact you should not even own a Mac, but I do not have a computer to play games, I do sound and video editing on my computers, and I would not dare do that on a PC. I am also a graphic design major now, and photoshop, illustrator, and in design are so much slower on windows, and are so backwards compared to the mac versions. Honestly I do own a PC, and I use it for the things I cannot do on my mac, but I could live with out it. If there was a better linux for the Mac I would probably ditch my wintel machine.
I do not agree with Apple's warrenty thing, that sucks, and nor am I saying it is a suppior machine, however it serves it purpose, it is an exteremly high end powerful machine, and to the people who are video editing on a PC, you are missing out on Final Cut pro.