I went with the 3 GHz. Steve promised we would have 3 GHz a year ago, and I've been waiting. So when they announced it now, I couldn't resist
This is my setup (yet to be delivered):
3.00 GHz Quad Xeon
4GB 667 DDR2 FB DIMM ECC - 4x1GB
ATI Radeon X1900 XT 512MB SDRAM
Nvidia GeForce 7300 GT 256MB
250GB Serial ATA 3Gb/s drive @ 7200 rpm
16x SuperDrive DL (DVD+R DL/DVD±RW/CD-RW)
Both Bluetooth 2.0+EDR and AirPort Extreme
Apple Keyboard and Mighty Mouse
Apple Cinema HD Display (23" flat panel)
AppleCare Protection Plan for Mac Pro
To that I'll add two 20" Cinema Displays and three WD Raptor 10k RPM 150 Gb drives in a RAID 0. I also ordered the nicely matching Altec Lansing FX-6021 speakers.
Can't wait to set it all up!