Everyone telling you the P5N-E SLI is horrible for quads is correct. The Quad core his highly dependent on the GTL REF voltage at higher FSB clock speeds. Unfortunately, the 650i, and all ASUS 600 series boards in fact, cannot supply the quad the required GTL REF voltage it needs. This is a hardware issue and will never be fixed with a bios update.
There are a lot of great P35 motheboards out there. The main difference between some of the budget boards and the more expensive P35 offerings is the southbridge. Any board with an ICH9 SB chip will not support RAID. The Gigabyte DS3L is a good example of a sub $100 board with this SB. The ICH9R SB chip includes RAID. Boards like the Gigabyte DS3R and the DFI LANPARTY DK P35-T2RS have the ICH9R SB and can RAID.
If you want a motherboard that is easy to OC in the bios, get a gigabyte:
Gigabyte P35 boards
If you want a more complex bios to squeaze everything out of your overclock, get a DFI:
DFI P35 boards
The Abit offerings are popular as well:
Abit P35 boards
Out of the many ASUS boards, I would recommend the P5K or P5K-E:
ASUS P35 board offerings
(narrowed down to ICH9R boards)