Well, I did it! I ordered a Mac.

Two 3.0GHz Quad-Core Intel Xeon
4GB (4x1GB)
ATI Radeon HD 2600 XT 256MB
1TB 7200-rpm Serial ATA 3Gb/
1TB 7200-rpm Serial ATA 3Gb
1TB 7200-rpm Serial ATA 3Gb
1TB 7200-rpm Serial ATA 3Gb
Two 16x SuperDrives
AirPort Extreme Card (Wi-Fi)
Mac Pro RAID Card

I didn't go with the 3.2GHz processors because I couldn't justify another $800 for an extra .2GHz. Besides, 8 processing cores should be enough for a couple of years, . And I went with the standard video card because from what I've read, it doesn't have anything to do with editing/encoding video. Besides I can always add an aftermarket video card later.

The thing that convinced me was that I can use Boot Camp to boot up Windows and continue to use Vegas 8. But I did also order Final Cut Express so I could get my feet wet in the world of Mac editing.

Now I just have to wait 2-3 weeks.