RGM beat me to itJust to pipe up with my own experiences: I didn't slide my motherboard in at the right angle the first time around and I actually got one of the tabs stuck in my ethernet port. Oops!
I was going to post a couple of pics of my new rig up, but I developed a (small) problem: the stock CPU fan seems to be buzzing for some reason, or some sort of audible sound at the very least. Is that cause for concern? The RPMs seem to be okay though.
Yeah, I've done that before. I've put together a PC and while plugging in things, I wasn't sure why the port felt extremely tight and the cable wasn't going in, turns out the tab went into the connector instead of around it.
As for your fan buzzing.. make sure the fan's cable isn't touching the edge of the fan blades. The stock Intel cooler's design wraps the fan cable around the fan but the loose cables can sometimes touch the fan.