The Thermaltake is cheap and cools effectively. See the review at
VR-Zone. The design is not as refined mechanically and somewhat noisier compared to others, but you cannot beat its $8 plus shipping price. (Check Pricewatch for price.)
If price is no objection, here is a high end alternative at
Cooler Star. The Thermoengine
ARKUA 8568 with a copper core. It should give you another couple degrees improvement over the Thermaltake, at a huge price increase.
AkumaBao, I don't think that Thermaltake makes any
higher-end h/s fans for the P4.