Another +1 on the chair. I have an Aeron - best investment ever. I have my 2 just at eye level (would mind them being a few inches higher). My Edirol 49 key controller is directly under my monitors, and my two gear racks are off to either side. I have a small 7" monitor connected to the VO booth camera right above the right monitor. I have an L-shaped desk, which is awesome too, because I have my Mac workstation in front of me, and my laptop and PC on my side All in all, I have 7 monitors surrounding me :-).
I tend to work on different halves of the desk, so I have video on both sides - if I'm editing on my left screen, I tend to move my chair to the left so I'm more centered in front of it, and there's video just to the left of it. If I'm mixing on my right screen, I move to the right, and there's video just to the right of it.
I don't have a control surface, but I do have a Frontier Alpha Track, which give me a bit of a tactile feel to the mix. I don't use it much though. I'm most likely going to sell it and get a larger surface.
I also have a Kensington Expert Mouse track ball (has 4 macro buttons). The buttons allow me to get in and out of expose, significantly increasing my productivity and speed around the computer, and it's fairly ergonomic.
What I do want is a Wacom Cintiq to work on. I think it would be awesome to be able to use one to draw in automation and sample-level editing and all. Probably would be pretty cool for mixing and plugin editing as well (especially if you can use it without a stylus!)
I've heard the Jazz Mutant stuff is pretty sweet to use as a controller for plugins as well, but I've never been able to play with one :-(