You are going way overboard for what you need. My laptop is a 2ghz core duo with raedon x1600 and I can run HL2 just fine. In fact it's quite hard not to sit in class playing CS-Source instead of paying attention. This is all done with 19v at 4.74amps. In fact I was playing oblivion at lowish settings with a decent FPS.
Anything you want to know about watercooling you can ask though. My home PC is fully watercooled, along with the past 3 PC's I have built and overclocked. This includes CPU, motherboard, & GPU being watercooled w/ a 2x120mm fan core. My last setup combined 2 seperate computers, both watercooled & connected to the same resevoir (~4gal container on top of the 2 computers) connected to a bunch of towers to evaporate the water for much lower temps, even without a fan.\
Also, you don't need to cool the SB, especially at stock speeds. Most motherboards don't even put a heatsink on that. Ram.... well I have yet to see a waterblock that I would trust to put on my ram without putting too much stress on the PCB of the ram or the motherboard connection. Just put a small quite fan to get airflow on the ram and keep it at stock speeds and you will be fine.
The only reason I used watercooling is to overclock anyway. For the most part, at stock speeds a decent fan/copper heatsink w/ good thermal paste is just fine. But when going from 1.8ghz to 3ghz daily and increasing voltages etc, you put out too much heat.