I'm almost through completing a similar project (
http://forums.procooling.com/vbb/showthread.php?t=8639). I was initially going internal until I found out my heater core with shroud was ever so slightly too big. I'm cooling a Pentium 4, 9800XT and northbridge using Danger Den RBX, Danger Den Maze 4 and Danger Den Z-Chip, respectively.
For you, I'd suggest a the Danger Den RBX (I don't believe the White Water is in 64 bit flavour yet), Silverprop Fusion and then as far as your hard drives I don't know of any blocks, so imagine you'd have to make some yourself. Have a look in the "Water Block Design" forum for that. For your pump I'd suggest a Swiftech MCP600 but if you do make HDD coolers then you may wanna move up to something stronger like the Iwaki MD20RLZT - but that's serious stuff! It's way bigger and way more expensive!
I think that about covers everything. You might wanna make yourself a relay for the main PSU to turn on the other:
http://forums.extremeoverclocking.co...280#post727280. Hope that helps!