If you are about balance/clarity, a 6-8inch bazooka tube would add just enough "thump" to your system. I you want a "wake the nieghborhood" system then get 2 tens/twelves. I listen to alot of techno/rave which doesnt require rap music heavy bass so the most i've ever addad was 1 10in. Best thing you can do is take a CD to Best Buy or where ever and play the music you normally listen to. Have them demo 1-10, 1-12, 2-10, 2-12, and then a bazooka tube. It's all about balance for me.
