I don't know if you're aware of all your options so : here it goes
Depending on your time table (that is : when you intend to have your whole setup up & running) and if you're a gamer at heart with latest games & all you might want to consider 3DVision as another possibility, preliminary beta driver performance reports are great in SLI & TRI SLI (two & three cards)
whereas some people reports that even just a 5970 isn't that great over a 5870, higher FPS but less fluid overall experience ...
that's only a suggestion though, and since I don't know what you want...
thanks, whismerhill
basically, i want to play flight sims (that includes space combat sims) and fpg/rpg games on 3 monitors, and to be able to watch movies and tv across all three monitors. if i can do both, then switching from one 30" to 3 24" monitors would be okay with me, and likely a lot less $$$ than buying 3 30" monitors.