I'm curious if you'd get better temps with your CPU cooler drawing from the right side of your case, rather than the GPU which is bound to have hot air.
I found that when using that orientation with my CPU cooler and my old 8800GTX/4890 the idle temp would be much higher, although I guess load temp isn't affected too much..
That's what I'm thinking too, but when I first built the system I didn't have a graphics card - I only got the 5870 last weekend so I haven't had time to fiddle around yet. I'm also tentative about moving the cooler because I have all RAM bays populated with high-profile RipJaws-X DIMMs and the cooler fits fine with all the DIMMs installed when pointing downwards. I'm not sure if it would fit the other way - in fact I don't think it does as that's how I tried to install it to start with.
Since getting the 5870 my temps haven't gone up at all really. At idle the 2500K is at mid-high 30s and at full load it's around low-mid 60s, and my 2500K is overclocked to 4.3GHz too.