Headphone jack won't work in new Mac Pro?

I'm using a new Mac Pro today, and couldn't get the computer to recognize headphones.

Solution: Push harder than you'd think. The new Mac Pros have a clicking socket. If you push it in all the way (requires a little force), you'll feel a click, and you're good to go.

Also, the new Mac Pros have no Firewire 400 ports at all (only 800)! I didn't realize they'd carried that through from the Macbook Pros.