BTW, it's not only for the software, but for the OS. My sister just recently got a computer with Vista on it, and I have to say that it is much more disappointing than I thought. It's nothing compared to Leopard.

If you do get the Mac Pro, make sure you get an external HD for TM. I got a 1 TB external for under $200 (around £100), so it won't kill your wallet and it saves you a lot of time.