Budget Workstation (HW config suggestions request)

Hi all,
I'm looking to get into compositing and would like to start with Combustion. Unfortunately, I can't afford a *real* workstation.
I've been (obsessively) looking at the systems that are on ebay.
Do you think that it would be preferable to go with an older dual Xeon (my budget will probably cap it at Dual 2.4...if I'm lucky) or rather go for a 775 based HT cpu (I probably couldn't go higher than the 540)?
Also, I'm guessing that it's worth it getting the most basic workstation card (FireGl, Quadro) rather than getting a better (equally expensive) consumer card. What do you think?
Is it worth downgrading the whole system a bit simply to have an AGP (rather than PCI-E) slot to afford a better card? (ie. Are older middle/top of the line cards better than the most basic PCI-E one?)
Is it more advantageous to get the system running on a smaller SCSI disk or just go for the SATA? (I'm going for a similar price range comparison)...or is the main reason for SCSI HDs the video rather than the OS?
I know you've seen similar threads before. I've been looking for these comparisons for two weeks now. I simply couldn't find the answer to these questions and I know that the are many *free love if you want it* much more experienced and savvy professionals on here.

Thank you very much for even taking the time to read the post.

Cheers,
isotrope

Dude, I cannot streess the point just mentioned about RAM. Combustion eats ram like Joy eats Salami. It just can't resist it!!

Also take a look at the Geforce FX 5950 ultra. You can then convert it into a Quadro FX 3000 with a little bit of twiking. Search the web for that! I have it and the performance is clearly improved.

Hope it helps...

Sam

If budget is an issue, I'd go for a fast single P-4 machine. Dual mobos add significantly to the budget, and are only faster in certain situations. To echo, spend money on RAM (but 3 GB is the max you can use under the current environment), and if you can, add a dual-drive RAID 0 to keep footage (_NOT_ workspaces or critical data!) on. That will speed up workflow. nVidia cards seem to be the most reliable with C*.

-jeff