Building New Computer, Need Help With Choosing a MotherBoard

I've decided to switch from an AMD based computer, to Intel, because even their slowest quad core is faster that AMD's fastest. But this leaves me with a few questions, I had learned all about AMD motherboards, but now that I'm going with an Intel chip, I have something to learn.
First off, what motherboards would you recommend? I'm looking for sub $100 boards, but if its a little over, I don't mind.
Requirements:
Must run be capable of running Q6600 (I'm doing 3D renders, so I need a Quad core)
Minimum of one PCIe 2.0, and if possible, 2 (don't both have to be x16, but should be when running single card)
2 or more PCI
Room for a dual slot fan on one of the cards (2 PCI must still be open)
ATX, or ATX extended

I have one last question, if the FSB of the chip is, say 1066, is there any point in putting in 1600 ram, or are the numbers not related? And is there going to be a huge performance difference with 1066 vs 800 ram? Also, if you have DDR, wouldn't you get 800 RAM if your FSB is 1600? < before anyone complains, I see that there was a topic about this, but neither the questions, nor the authors were perfectly clear.

Current Motherboard Considerations:
http://www.newegg.com/Product/Produc...82E16813130180
http://www.newegg.com/Product/Produc...2E16813130159R
http://www.newegg.com/Product/Produc...82E16813130185

You're going to be looking at a P45 mothboard, and will need to spend upwards of $150 to get one with two PCI-E 2.0 slots. Otherwise, you can get a single PCI-E 2.0 x16 slot for around $100.

All you really need to know when it comes to Intel CPU's and motherboards in regards to RAM is that the difference in fsb (DDR2-800 to DDR2-1066) is basically just more room to overclock (matching the CPU's fsb to that of the memory). Try to go for the lowest possible timings though, such as 4-4-4-12. That's where 'speed' becomes a (small) factor.

So, with the Q6600 the multiplier is x9. It's default FSB is 1066. Intel processors are 'quad pumped', so we can divide that by 4 = 266mhz.

DDR2-800 is 'double data rate' so we can divide that by 2 = 400mhz.

What this means is that using DDR2-800, we can overclock the Q6600's fsb from 266 up to 400 before we have to overclock the memory (Which I wouldn't recommend). So, 400mhz x9 = 3.6ghz.

DDR2-1066 /2 = 533 x9 = 4.8ghz.

A P45 motherboard has a default fsb of 1333, so you can get a "free" overclock on the Q6600 up to that fsb (1333 /4 = 333mhz, x9 = 3.0ghz). This shouldn't even require you to change voltages or anything!

So basically you definitely don't need anything more than DDR2-800 as it'll give you room to OC all the way up to 3.0ghz.

X48 motherboards btw have TWO PCI-E 2.0 x16 slots for Crossfire, though if you're 'just' using the 4850 go for the P45 board and Crossfire as the X48's are more pricey. If you're looking at using two 4870's though down the road.. then I think you should consider the cost of X48 as I believe the DDR5 in the 4870 see bottlenecks on P45's PCI-E 2.0 slots that run at x8 electrical when in Crossfire.

Hope your brain didn't explode and that makes sense

Good luck!!

Thank you both, great suggestion, and that was an incredible explination, and helped me to understand alot more, so thank you!