I tried Eyefinity for a few months with three 23" screens, but after that I now just really wish I would have gotten a 1 large screen solution, like 40". I ended up selling two of the screens and for now I am using the one 23" and am very happy so far, much happier than I was with the three. I would suggest one large screen, I mean yeah you get extra FOV in Surround/Eyefinity but it's difficult to really utilize unless you are sitting a good distance back, and that sucks. If not, you are too focused on the huge middle screen to begin with to really take advantage of the extended FOV.
Also, triple monitor gaming takes a hit in performance (SLI 480's wouldn't see a huge hit, but no one knows yet how Surround scales) If you like all the eyecandy and stuff then you will have to be ok with letting a bunch of it go in order to have the extended FOV. This was another reason I ditched Eyefinity. I'd rather have everything at max at 2048x1152 than medium-high with little to no AA at 6144x1152.
At first I thought I would never go back to a single monitor again, but then after weighing it out, I was happy to let it go. That and when the **** are you going to get your support for multi-monitor gaming?
mi dos centavos.
edit: And people's setups, to me, looked far more impressive and comfortable with like a wall mounted 40"-46" and the desk right in front of it. That is a heck of a slick setup there, it's my dream one day.