I've been running about 500 MH/s for about a month - as soon as I can convert enough bitcoin, I'll probably be doubling that with another card, hopefully in a few weeks - if bitcoin prices hold, I'll add more as funds arrive - got the space, the juice and a cool room... it's a no brainer....
Are you sure about that? We just had a huge jump in difficulty. If it continues, two weeks from now your bitcoin production for a given Mhash will be ~30% of what it was yesterday (before the increase). Even then, that value will only hold another 10 days before it falls again.