I second the MCX462-V with Panaflo 92mm fan. You can get the heatsink at www.sidewindercomputers.com for $31.95. You can get a Panaflo 92mm L1A (41-42 CFM @ 27db) at www.casecooler.com with RPM signal for $9.95. I'm planning on getting 92mm to replace 80mm I have on my MCX462-V right now. I'm getting the 92mm to cool hot running components around heatsink, because 80mm Panaflo H1A's airflow is slowed down by heatsink to much before it gets to other components.
BTW 80mm fan on this heatsink cools better because of smaller motor hub, but the heatsink cools so well that it doesn't matter in my case. I would also recommend you buy som Arctic Silver Ceramique as it seems to perform better than AS5. My CPU runs 5 degrees fahrenheit cooler using Ceramique versus AS5.