I have the Q-Pack and it is a beast. I highly recommend it for a mid-level gaming computer. The two drawbacks:
1. You will have great difficulty fitting a standard size PSU in this case. This case ships with a non-standard size PSU, and while you can jam a regular PSU in here, it will be a cramped fit, and you will likely lose one 5.25 drive bay.
2. I think that you will run into trouble fitting a water-cooling system into any mATX case, much less the Q-Pack. If your WC system is serious, then get a serious case, like the Antec 900 or 1200 or whatever.
I love my Q-Pack, but it is definitely not for everyone.
Cheers,
Stefan
AMD 5600+ @ 3006mhz
2 Gb Corsair XMS2 @ 864mhz 5-5-5-15
EVGA 8800gt 600/900
Apevia X-QPACK2
Gigabyte MA69VM-S2
Acer 24" x243w
10387 3Dmark06