In a lot of professional music production situations, I've seen they were using Mac's, because they're good at that...?
We have them at school in the graphics room, they do pretty much whatever we need and if we need to use a program(2D Design, for the laser cutters and stuff) that will only work on Windows, we just use an emulator.
Anyway, I have(since 2002-3) an Advent 3000 Series, it's not the best, but it does what I need, runs SA, records, etc...
I just got an HP nc8000 laptop a few weeks ago, it's decent for recording drums and browsing the interwebs and is pretty fast considering it's age, as with my desktop, runs faster than a lot of my mates PCs, that are much newer..