If you can wait a few months, nvidia's next generation should be out within 6 months. Or if you have to buy now, get one of the new AMD cards that do 3 monitors. And then buy 3 monitors

Stand the monitors up into portrait mode, and you'll have just about the best display system for AH you can get without going for a full projection system.
The nvidia card you mention (295) may get you better framerates than the AMD card, but the AMD card will push 3 monitors and it should work perfectly with AH without any driver or game tweaks. AMD also finally implemented angle-independent ansio filtering, which should reduce texture crawling.
I'd get AMD or wait to see what nvidia's next generation can do. The next nvidia generation is pretty much a single-chip supercomputer that also happens to be optimized for graphics, and it'll either be amazingly good or a massive flop. Either way, it ought to drive down prices
