Since it may be hard to find the 3450's you might look at a newer card. 2 3450's in sli were pretty powerful at the time. Now I think a powerful desktop card would beat them both in sli.
We just came across some 7800GTX's; a 7950 GX2 and a bunch of other workstation stuff.
I don't know what to get I mean, I want something that will be fully utilized by programs that can use them so I don't know if going with a gaming card is worth it.
I'm still on the fence looking at the grass and the sidewalk... don't know what to do really!