I'd second Jipstyle's recommendation of the Corsair premade water systems. In the same price range as a decent air setup, and as easy (if not easier than some) to set up. It also reduces noise by moving the CPU cooling fan into the same place as a case fan (killing two birds with one stone), and in most cases reducing the total number of fans in your system.
Choice of leadership graphics:
NVIDIA Quadro NVS 280,
NVIDIA Quadro NVS 400,
NVIDIA Quadro4 380 XGL,
ATI FireGL T2-128,
NVIDIA Quadro FX1100, and
NVIDIA Quadro FX3000
Get your CPU cooling sorted out first, but I'm still guessing that a decent amount of noise is coming from the graphics cooler. The workstation market isn't the same as the gamer's desktop market, so these are likely basic reference cooling designs. Nothing like the big heat-piped coolers you'll see on some gamer cards. Basic OEM coolers tend to create a lot of turbulence and other resistances to airflow that increases the noise from the graphics card.
If your efforts with the case fans and/or CPU don't get the results you're looking for, Something like this Zalman VGA cooler
for $30 might help. Unfortunately, you would likely also need some passive HS for the RAM/VRM as well, which may cost as much as $20 more.