AMD's in general overheat more and perform less than Intel chips. Yes, AMD is cheaper, but it sounds like you're at least semi-serious about music production (otherwise you wouldn't have made this post) so I'd say #1 is spend a bit more and buy an Intel CPU.
As for which CPU I suppose it depends on your budget? No need to go for something ridiculous such as the
3930K.. But other than the high end i7's there's basically just $100 jumps between i3, i5, i7.
The i5
2500K is four solid cores and is priced around $235.. I'd say look at that one!
Also, What program do you use for music production and How much RAM do you have?
Have a good one!