I've got a first generation Intel i5-750 2.66ghz processor which is overclocked to 3.5ghz.
I've got a older cooler master v8 as my CPU cooler. In this summer southern California heat I get idle temps of about 38c and occasionally about 44c during idle.
My case is an Antec mini p180 with a 200mm exhaust fan at top and a 120mm noctua 800rpm rear exhaust. I also have a noctua 1300rpm as the fan for my cpu cooler and I've zip tied an additional 120mm fan to the cooling fins to push more air from the cooler and then another 2 noctua 1300rpm 120mm intake fans in the front of my case. My thermal paste is Arctic Silver 5.
I haven't stress tested my rig in awhile but usually when it's fully loaded I hit temps of around 60/70c.
My rig is powered by a Thermaltake 750w power supply with 7 hard drives connected. I'm hoping that's enough to run everything that's hooked up.