Hey man, I thought I would elaborate on my build
I am running a Q6600 at 3.4ghz from 2.4ghz right now on stock cooling and will be doing more once I get me giant new heatsync.
Your IP35-E is a very nice board, it is just like the IP35Pro but it does not have SATA RAID, which alot of people do not use and runs on the P35 chipset. This is an awesome chipset that really lets you crank up the FSB [front side bus] and this is how your clockspeed is raised. The E6700 you have is a great overclocker as it has a higher multiplier which allows you to use a lower FSB speed. Your FSB speed is dependant on your CPU and RAM. Even if you have regular DDR2 800, which you probably do, you can theoretically hit 4.0ghz before your RAM starts being the limit.
Depending on your cooling, I would lower the CPU multiplier to 9, raise the FSB to 400mhz and put some more volts through the chip.
Make sure to lock the PCI-E frequency at 101mhz so we dont fry any video cards

I can easily see the chip going near 3600mhz. For voltage, do the max alloted by Intel officially which is 1.35 or 1.375V.
I almost bought that board, but settled for the Gigabyte P35-DS3L for its all solid capacitor design. Not to worry tho, that Abit is a nice board and uses japanese capacitors which are still grade a!
And the quad is great