Thanks a ton! That will save me a lot of money! I was told that running two GTX 480s would generate so much heat that I would need the Twin Frozr version or add a water cooling unit.
No, whoever told you that was telling you the opposite of the truth. Is that a lie? No, just a mistake that happens to be opposite of the truth!
The Twin FROZR cards vent into the case. That means your case gets hotter. What effect this has on your cards depends on how much and what direction your case ventilation has.
The standard card blows most of its heat out the back of the case, through a grille that covers the second slot. So, the standard case heats the case much less.