I like to build my own desktop PCs, and I happen to know that I've got a rockin' processor and graphics card both, so my system definitely has some punch to it. I also know that I didn't get the best motherboard on the planet.
I know that the motherboard houses the various buses that the processor uses to communicate with all the other various hardware on the board, and I'd like to know how the speed of those buses affects the overall performance of the PC. In other words, what are some common "gotchas" to watch out for, and where to I really not want to skimp out on general motherboard performance?
This is not a "which motherboard is the greatest" question, I'm not looking for a specific model, I just want to know which features I should watch out for when shopping on my own. In the same line of thought, this is also not an "is an Intel better than an AMD motherboard" question, under the same line of thought.