If I might suggest something a bit different. Given that you indicated that you're not that interested in FM and are primarily interested in music, I'd suggest a good integrated amp instead of a receiver and put as much money as you can into two great stereo speakers than a lesser 5 speaker system. Stereo is, IMHO, still the best way to enjoy music, and I've found that much of the really interesting music is still only available on plain 'ol CD. I would add a HSU subwoofer, probably a VTF-2, but you have to figure out how to balance it to your speakers.
In terms of TV, I've been evolving my Home Theater for over 20 years and what I've found is that the biggest single improvement is being able to run a stereo signal into your music system to bypass the TV speakers. That alone will be a huge improvement. The second biggest improvement is the sub. Going to surround, while nice, is nowhere near as big in terms of your overall enjoyment. I say this as one who has a 7.1 system driven by the Yammy 2500 that folks are suggesting for you. It's very nice, but when I want to really enjoy music, I go downstairs to my 2 channel music only system driven by a Roksan Kandy integrated amp.
So, given that you indicated that you're twice as interested in music as tv, and hint that you listen to a wider variety than just 'head banger' stuff, my suggestion would be to get a system that is the best for your music and then just take the improvement that it will give you for your TV watching which will be substantial. Easier to set up in an apartment too, speaking from my own past experience.