Here's my gaming setup:
My monitor, an old chroma-luma/RGBI combo I got with my Commodore 128, which provides pretty nice composite video.
To the left of the monitor, my Nintendo, modified to disable the lockout chip when Super Mario 3 stopped working. (Yeah, that's 32X DOOM. No, I don't have a good excuse.)
To the right of the monitor, hanging partway off the desk, my Playstation, purchased for $7 at a garage sale about eight years after it became outdated.
On top of the monitor, my Sega setup, complete with Sega CD and 32X. Now if I could just get some six-button controllers...
I couldn't very well have it
under the monitor (well, I could tape it to the underside of the desk, but the swap trick would be a lot harder,) so it's behind it. Sega Saturn: for when you absolutely
must play some Street Fighter Alpha or Darkstalkers.
The magic of the whole setup: an A/V switcher, purchased for $5 at a thrift shop. No more cable-swapping, hooray! Left to right: NES, Genesis, Playstation (didn't have to tape a new label to this one,) Saturn, turntable (yes, I own a turntable and records.)
Not pictured: sub-mediocre $20 speakers, got 'em for $10 during a sale at Radio Shack, on either side of the monitor.
Sharing some pictures of my arcade setups:
I recently sold Cannon Dancer though. It's too expensive to have lying around. I've one credit-cleared it, and am pretty satisfied.