Agreed with peterhuang. $150 won't get you a good watercooling system. So just go for the Tuniq. Which is about as good or better than cheaper watercooling kits.
The Thermalright 120 Extreme with a really good 120mm fan on it will cost about 80 bucks but will offer better cooling than the Tuniq. That's the best air but the Tuniq is good enough really.