Idle 33c and load maximum 70-74c, but its NOT representative because currently where I live there is a record summer heat and my room temprature is almost like a sauna. In the Netherlands we are close to breaking our heat record in 1944.
My cpu is +10c hotter then usual as well, its pretty damn hot atm where I am, so perhaps someone else could provide a more realistic answer.
I can imagine this card getting no hotter then 66c with normal circumstances considering my case is actually pretty well ventilated, although it was never built for unusual circumstances like this, hehe.
In regular circumstances, my case is extremely well ventilated, thats why I'm personally not that worried. But we'l see, my second card isn't coming probably untill next week. Currently just enjoying a single card.
As for tower advice, I cannot say. But I use Corsair 450D with 6x AF quiet edition fans from Corsair. Just be sure you don't sandwich them, you'l need a mobo with spaced SLI.