You aren't going to get a definite answer over which sounds best, because they're both HQ lossly codecs and each will have their devotees and their haters.
Just pick the one which best suits your needs. Looking at what you've written so far, I'd choose 320K MP3.
Audio: MacMini / AEX > AVI DM10 + BK Gemini II sub; Visual: Samsung BD-C5500 > Panasonic TX-L47ET5B.
Head-fi: various, but most often Sennheiser HD-580 or RS-180