Bill I think you could get yours cooled down to idle way less than that. After all my issues (and mb bios not reporting correct temp) my CPU idles at 28C @~1500rpm and hours of doom3 underload highest it gets is 47C. Only other fan is the case fan that is barely turning (on a fanmate2 at lowest setting). I could turn up the case fan and it would help, but I dont even need to really do that under load. My PS has dual fans(one inside, one outside), but they are so quite you can't hear them at all.
Also, my at idle CPU runs 5C COOLER than the case air temp!! This is because I have a port on the side of my case that has an air duct that goes down to the CPU fan. So the CPU is cooled with fresh outside air, so it's cooling is more efficient as it's colder without having to turn up the fan rpm!
I'm using Artic Silver5, before that I was using Artic Alumina. Not a huge difference between the two. Ceramique is the other non-conductive paste they offer, which performs better than AA, but less than AS5. But I might have gotten a degree or two lower.
I can O/C mine to 3.2g from 2.8 without crashing, and without turning up the voltages. I may be able to go higher with increasing the voltage. But doing that I do not get much hotter than when running at 2.8. I don't OC though as I have not needed the extra power yet... I'd say you could get pretty close to where I'm at. I'd say with the right setup (side vent helps a LOT, and is like a "free" mod), you could be at least down to around 35C idle, and 58C load, maybe better.
You first need to figure out which you want the most.
1. Coolness, 2. Silentness, 3. Less mass. My Zalman is under the max mass for the MB so I don't have to worry about moving the case and ripping everything to peices and then it falling and taking out more stuff. It's silent or close too it, and cools pretty good but not the best of what is out there.
I do need to get the air-duster can out and blow the dust out of it, as it's clogged up last time I looked and idle is 2C higher now. This room got really dusty from moving a couch and other things, so I need to clean up some.