ARC makes a massive improvement in my room, and does a far better job than Audyssey XT32. I'm sure I could improve things further if I had the time to experiment and tweak, but the default 20-minute setup sounds great to me. Anthem is releasing a new line of receivers/processors in December, and I'm sure those will do an even better job of utilizing ARC (new calibration mic for one).

Axiom M5HP VP160 M3 ADA1000
Anthem MRX 720
SVS SB-3000 (dual)