Hahaha! Oh man, reminds me of the good ol' days when SETI.USA was #1. Used be some serious whip cracking between members, LOL!
This is good stuff. I'm very glad both of you joined up. Light a FIRE under that man!
You could easily put 3 GPUs in that board with no problems...er...other than the problems of 1. strong enough power supply
2. big enough case w/ adequate cooling
Which GPU did you end up with in that build (did you end up with the GTX280?), and which are you "maybe" thinking of buying for a second one?
Remember the cards do NOT have to be matched - so get a more powerful one for the second card, if you can swing it.
Please let us help with the selection - and definitely mention your budget! Not all GPUs are created equally, and even "higher numberd" cards don't always crunch more than a "lower numbered" card - it's a big marketing scam out there, the way they number these GPUs to get people to buy them.
Thanks for keeping us updated and we'll pitch in with any crunching knowlegde we have built up over the last couple years of GPU use.