If you need an inexpensive and relatively small heatsink then FrostyTech has a review you should check out.  At a mere 125x68x160mm and 588g the Evercool Venti HPQ-12025 is tiny compared to many on the market and at $30 it is significantly less expensive than larger competitors.  With that small footprint you could be forgiven for thinking that performance would suffer but FrostyTech's testing shows it to be a solid midrange performer and still reasonably efficient when running the fan at its lowest speed.

"Airflow is driven by a single 120mm PWM fan whose snow white 7-bladed impeller rotates at your basic 2200RPM to 800RPM. Noise output is moderate. Because computer enthusiasts tend to be picky bunch, Evercool have tossed in one extra set of wire fan clips."

Here are some more Cases & Cooling reviews from around the web:

CASES & COOLING