Which audio apps are you currently using and/or thinking of using on a PC? If you're doing Pro or near-Pro quality multitrack work, I'd honestly stick with the Mac.

Before you go out and buy yourself a Wintel, Apple has released software to allow you to legally dual boot an Intel-based mac between OS X and MS Windows.

Yeah, it's a public beta right now, and will be shipping standard with Leopard which I think is sheduled to come out this summer or fall.

If you are planning to use the computer for sound production then my best advice would be to stick with a mac. I am very interested though why you could want to move to windows. Also if in the end you make the decision to go to windows, don't by a DELL look around and you will find better deals.

This is a very unusual situation people normally switch from windows to mac not the other way round.

having used both for music production, as well as providing support to various studios on both platforms, the mac is much smoother for the simple fact that audio and midi is integrated into the os.

you can connect almost any hardware and it just works, and seamlessly switch between apps without audio resources being locked up by one app or another.

I have dell studio xps 9000 for sale.
If interested link me at jodain08johnson@yahoo.com

specs:

Processor: Intel® Core™ i7-920 processor(8MB L3 Cache, 2.66GHz)
Monitor: 21.5" Dell ST2210 Full HD Monitor with VGA cable
Optical drive16X DVD+/-RW Drive
Memory: 6GB triple Channel DDR3 SDRAM2at 1066MHz - 4 DIMMs
Video card: nVidia® GeForce® 310 512M GDDR3
Hard-drive: 500 GB 7200 RPM4 SATA Hard Drive
Mother board: Intel X58
4 memory card slots at front
AY410 2.1 Stereo Speakers with Subwoofer
Dell Studio Consumer Multimedia Keyboard
Dell Laser Mouse