What goes wrong if it takes a week?
Can you post a link to specification page of your motherboard at intel.com. That gives info about compatibility of your motherboard with different processors. You wouldn't want to buy a processor that's incompatible.
There's no "best for a mobo". If it's compatible, it works. There's at most a "best for you". But you didn't tell anything about your needs.
So, assuming all these processors are compatible with your mobo, see what they say about them at tomshardware.com.
I have an Intel Core 2 Duo E4600 and my mobo is Intel DQ965GF. I wan to upgrade for a Core 2 Quad Q6600 or Q6700 processor. But I bump into EBay and found a a Core 2 Extreme X6800 for $215 and Core 2 Quad Extreme QX6700 for $288! I think the prices are very reasonable. I just want to ask what is best for my mobo? Is Core 2 Extreme X6800 better than Core 2 Quad Q6600 or Q6700? Or Core 2 Quad Extreme QX6700 worth to buy? Please help me on this ASAP!