SPCR

If I want to build a PC for music creation and editing, which processor would give me a quieter system at both idle and full load: An i5-6600T or one of the regular series (6400, 6500, or 6600)? Assume I won't be messing with underclocking/undervolting the CPU. I'd use an aftermarket CPU heatsink/fan, not sure exactly what, but it would be a reputable brand.

Welcome to SPCR.

Go with a regular i5. It'll have the same thermal profile of the T up to the point where the T would be running at 100% load...and then if you need more horsepower, you have it at hand.