I haven't turned the knob on my sub on my Creative Cambridge Megaworks 510D past half way either. I'm not into techno, nor rap, so bass is kinda out. I like 80's rock, and some 70's, so bass wasn't a biggy back then.
However, some songs, a few from Metallica do have massive bass to them, and sound better with it turned up more. However, I don't mess with the knob, i just mess with the EQ.
Athlon 64 X2 7750 Kuma @ 3360 Ghz @ 1.475V (14.5x223)
(NB: 2240, HT: 2015)
Sparkle GeForce 9800 GTX+ (755core, 1350 mem)
Onboard sound (yuck)
4GBs Mushkin DDR800 (6/6/6/18/24 @ 928mhz)
2x74GBs RAID 0
2xWD 1TB HD RAID 1
Plexter DVD Burner