45-50C at idle is VERY normal for a Q6600 with the stock cooler.
Best recommendation is to replace that stock cooler. Even if you don't OC, you'll want to replace it if you plan to use your system for gaming, encoding, etc. Anything that'll put your CPU at say 50% or greater load, wouldn't be a bad idea to get an aftermarket cooler.
The Q6600 runs kinda warm.
If it'll fit. I'd get the Xigmatek HDT-S1283 cooler. Price on it is pretty good, and Tom's Hardware did a CPU cooler review and named it best. Plus it's relatively cheap ($35 or so).