First off, I love macs, and have used them for 12 years. If I was using a computer for multi-track recording I'd use a mac. If I was using it for concert recording, I'd also use a mac.
In my situation though, the new computer is serving as a basic daw, but more so, it's simple data management and the pc does this faster and easier than a mac. I'm using the pc as a media server and a very basic editing platform, i.e., cdwave or wavelab>flac>foobar. These programs simply do not have equivalents on the mac, not that I've found. Sure you can use itunes, but it doesn't burn DAO. Sound Studio works ok but it's a cpu hog and it's buggy. Foobar is simply one of the most powerful audio apps I've used, it's a thousand times more powerful than a program like itunes. When I'm done converting my collection I should have around 500gigs of music. The pc is faster and cheaper to manage this kind of data. Keep in mind I'm typing this on my powerbook

The imac is a great machine at a great price, for a mac. I bought my dell through the dell outlet for $500, 3ghz p4 800fsb, 160g drive, 16x duaI layer dvd, 1g ram ect... I could buy a mac-mini for that price but the performance of a mac-mini is complete shit compared to this machine, I bought one for my sister last year and it's slow as hell. All I'm trying to say is that for basic music/data management the pc is a cheaper/better solution for me. I'm still lusting over one of the new mac book pros though!