Old, old debate...a few of my $0.02....

1. Macs are still more expensive. If you open one up inside, you'll see why. They are marvels of engineering and quality. Open up most PCs and you'll see bargain basement parts slapped onto a motherboard. Not so with Macs: well-engineered ventilation, sound absorption, simple parts replacement, parts quality, etc.

2. They are still MUCH, MUCH less likely to get a virus or other malware. It's the nature of the Unix operating system.

3. I know several people dual-booting XP and Leopard on their Macs.

4. I have DP, Logic, Protools, and used to use Cubase. DP is used more by film composers than songwriters in my experience. It's because it has a lot of unique features for composing to film such as gradually reaching a specific tempo at a certain hit point, tying 90 minutes of music together into bite-size music chunks (they literally use the term "chunks"). I would check out the forums on DP at www.motunation.com and see whether the latest version is stable. There were some real problems with version 6 when it first came out.

If you are considering the Mac, I'm surprised you don't have Logic Pro on your short list. It's certainly a good buy with everything included. Me, I'm a Protools guy and version 8 closed the gap on the weaker midi features compared to Logic. The new version 8 is much more songwiter-friendly than version 7 and very easy to use now, especially if you come from a "mixer and tape" world since it models that in software for a lot of it.

On the PC side, I'm surprised that you don't include Cubase in your short list. I'm not as crazy about it on the Mac, as Yamaha (the owners) are really more PC-oriented. Therefore the PC version is usually more stable than the Mac version. Cubase 5 certainly has a huge feature set - maybe more than most people need, but it's impressive.

Another app I'm becoming more and more impressed with is Ableton's Live. Especially the new version 8 is very impressive. It's definitely a composer's tool.

I would ask whether your main use will be for audio recording or for midi recording. If it's audio, then Protools (either PC or Mac) is still arguably the easiest to use with the most audio-centric features built it. Features like audio quantization to the grid or to a groove (that works), Beat Detective, Elastic Audio, Elastic Pitch, easy comping of multiple takes, etc. Right now, PTLE is very reasonably priced. Their entry level system is only about $300 including hardware AND software.