To be honest, i'm in a similar predicament. I'm looking to purchase a desktop mac within the next month or so with a budget or around £1300, I'm at university (although currently on a placement year) so i can the higher ed discount.
I'm trying to decide between a 3.06ghz Dual core iMac and a 2.8ghz quad core mac pro (I don't think I need 8 cores). I already have a 22" samsung monitor, although i'm sure the 24" iMac screen would be better quality... However I'm also sure for my uses (3ds Max / Maya work, photoshop, web design work and some audio recording) I'd probably prefer the extra cores and upgrade potential of the Mac Pro...
I keep popping into the apple store in liverpool and playing on both... I really can't decide!