ud3r or P5Q Pro -- which one is better for me?

Looking at these two boards, plus the ds3l for a new system which will be used for gaming, some video rendering, and will be overclocked.

I will be using an E8400 and getting the MSI R4850-512M single video card to keep things quiet (http://www.newegg.com/Product/Product.aspx?Item=N82E16814127370)

What is the difference b/w the P5Q Pro and the UD3R? The specs say that the P5Q Pro has less supported memory at a little lower slower speed (1233+ v 800) and 2 fewer USB slots, but has one more PCI 2.0 slot.

1) What does the mean practically for someone who wants to OC and doesn't need two videocards, and

2) What are the differences b/w the boards p5qpro, ud3r, and ds3l that the specs don't tell us?

Thanks in advance!