Oh welcome my child, for we have the wisdom you seek. (ah, couldn't resist!) MAYA is a very cool program, a friend has created some animations for me, first in Alias and now MAYA and some great stuff comes from there. I used to dabble in Electric Image, but let's not even go there! :)
First off, forget about Firewire with HD. You can't even run SD in uncompressed via Firewire.
I'm currently running a CineWave SD RTsystem with one Medea 240RT. Technically the Medea RT series is not approved by Pinnacle to run SD and especially not in RT..... but it is working happily here. BUT, the Medea RT series will not work in full, uncompressed HD. They're simply not fast enough. You should be able to do offline with it, probably no more than 25 or maybe 50% quality
Some basics for CineWave HD approved by Pinnacle.
G4 450 or above, including the dual processors
OS X is NOT supported yet, you must run OS 9.2.2
ATTO UL3D or Adaptec 39160 dual channel SCSI card
Harddrives include Maxtor Atlas 10k/II and 10k/III, Seagate ST373405LC and LCV, Huge Systems Media Vault 1000 Dual Max.
You can get the complete configuration guide all all approved peripherals at the Pinnacle Support site
http://www.pinnaclesys.com/support/display.asp?ProductID=416&SubDocTypesID=74
As for the monitors, etc.... All of that is up to your taste and exactly what you are going to be doing and whether or not clients will be in the room with you. I'll ask some of the current HD users to pop over here and let you know what types of setups they're running and that can give you a guide. Brian Shaw will probably pop in as well and give you some feedback on this.
I would strongly recommend ProMax as an initial phone call to discuss an HD setup. They setup my SD system and Ethan Ede has been a great asset to me in both the initial system setup and additional purchases later.
http://www.promax.com for the phone number.
For the time being, I'll list here what my setup is for the CineWave SD RT so that will get you started. Basically, for me to upgrade to HD at this point, I have to add the CineWave HD Breakout Box and get new drives. That's it. Of course, I'll add a new monitor, but I haven't gotten that far yet! :)
G4/533 Dual Processor with 640 RAM
40GB Internal HD
Adaptec 39160 Dual SCSI Card
Medea 240RT (not approved by Pinnacle for CineWave)
ATI All-In-Wonder Graphics Card (for 2nd monitor)
WACOM 12x12 Intuos Tablet
Dual ViewSonic E95 19" Computer Monitors
Pinnacle CineWave Video Capture Card with Analog Breakout Box and SDI Breakout Box
Sony UVW-1800 BetaSP recorder
Mackie 1202 audio board
Roland RSM-90 Audio monitors
Alesis 150 Amplifier
27" Philips NTSC Monitor
Panasonic AG-DV1000P MiniDV recorder
Final Cut Pro 3.0
Adobe After Effects 5.0
Commotion Pro 4.0
DigiEffects Cinelook
Adobe Photoshop 6.0
Cleaner 5.0
Eye Candy 4000
Xenofex 1.0
Hope that helps a bit!
Walter