Well, glad that's sorted then
At that sort of resolution I think you might need to look further upmarket, the GTX460/275, even in SLI, is likely to struggle with three large monitors, but I could be wrong- anyone like to comment?
Performance wise the GTX460 just edges the GTX275 out and with better scaling with cooler, quieter operation as added benefits.
If the new MB also supports Crossfire you might want to hold fire until the new HD6xxx series is released and see how they stack up.
Me, I LIKE cool and NEED quiet, so my choice would be the GTX460 and E-bay the GTX275.