I recently upgraded to a new iMac and it's wonderful. I am running Windows on it with Boot Camp - not because I want to but because the only way I can access my company's website/enterprise server is by using Explorer 6.0, which is not available on the Mac and the discontinued 5.0 will not work with their website (neither will Safari or Firefox). This is something you will come across from time to time, poorly written websites. I do not use windows for anything else, I use MS Office on the Mac.
It only uses 5gb of my 250gb hard drive so it is worth it. It is such a nice feeling to be able to boot back out of Windows though, the difference between the two OS's is so glaringly apparent on this machine.