Unfortunately I only have 2 monitors at the moment, I want to put on a third but someone else is using it. I don't know how you guys all manage with those set-ups.
My competition grade mousepad is probably the most obvious thing to you all, though maybe my sixy Sennheiser headphones will be noticed too.

http://i.imgur.com/K3iP0.jpg is the main set-up amidst the masses of desk mess I always have.
http://i.imgur.com/DpLqB.jpg and http://i.imgur.com/BCKtt.jpg are some pics of my actual PC - which is beastly. The white thing in the second one is a 30cm (12inch) ruler to give you an idea of the size. And yes, that is an old graphics card sitting on a pile of hard drives next to it.
The specs:
6 Core Intel i7 @ 3.33gHz (12 cores with hyperthreading).
Gainward Phantom GTX570 (factory overclocked, and massive).
Auzentech X-fi 7.1 Bravura (beastly soundcard).
16gb GSkill Ripjaws DDR3 (yep, 16gb).
Aside from that I don't think much else would interest you guys. Though I would like to mention it has 11tb (11,000gb's) of hard drive space.