I say save about 200 dollars for water cooling so that gives you 1300 to spend on the comp which is alooot of money. Get a good idea of what kind of parts to get and then here are the cooling options...
CPU: Swifty MCW5002-P (or A), Danger Dan RBX (he might like this better cuz it looks "cooler")
GPU: Swifty MCW50 (with 1/2ID tubing adapter) or Danger Dan Maze 4 (It's always a nice option to slap on some ram coolers)
NB: get a quiet (Below 25DBA) 40mm fan and slap it on the exiting heat sink
Pump: Hydor L30 as its cheap, dependable, identical to 1250
Heatercore: the good old 1986 Chevy Chevette
Plumbing: Clearflex 60, Metal-clamps, T-fitting, teflon-tape can all be bough at
www.mcmaster.com for cheap price in one place.
Water Additives: Dex-Cool or Zerex SRC with some colorful dye
I got most of my parts from
www.cooltechnica.com
Have fun