Let me add: If you mess up with the tubing and stuff, goodbye computer
Takes a lot of planning yes. Water cooling isn't needed in most cases, a good air cooler is great. Water cooling is for something like 4.2-4.5 overclock on an i7.
Things like your northbridge, mosfet and southbridge really don't need to be water cooled.. that's overkill. As long as you have some good airflow (not through a radiator) then it's A-Okay