Polk Audio is now making available a trio of headphones they are marketing specifically for Android users. The headphones are part of their UltraFit series and can be distinguished from the other sets in the series by the lower case “a” in their model number.
The top of the line model is the UltraFit 3000a.
I'm considering getting Polk Monitor 65Ts (or 75Ts if you think they're a better buy), a Polk CS1, and a BIC F12 subwoofer. Then, at some point when I have more money, I would probably get the rear surround speakers, though I'm not sure which ones I should get.