I just got the iMac for Christmas and my husband purchased the 3yr warranty so if Apple says the warranty is good, I'll take it with me. There are enough electronics to replace without adding an iMac to the list.
Dell's warranty is global, so I'm pretty sure Apple's is too after the feedback I've received.
My son worked at the Apple store and he and my husband thought it would be a great gift; I wish we'd known Apple was going to Intel processors, because I definitely would have taken the G5 back and waited. As a long time PC user the change has been frustrating, I should have known when setting up the imac the "Take control Lose Command" screen popped up
that I was in for a few headaches. I've kept my Dell for work since my apps only run on XP, cross platform sure keeps you on your toes (Linux at work)!