I have a 3x1680x1050 eyefinity group Then a 1920x1200 24 inch on a wall mount hanging above left of the eyefinity monitors that I have a dvr hooked up to. I also have a 19 inch tv monitor on the right of the eyefinity group for a fourth extended monitor so I can have teamspeak up and so forth while playing in eyefinity. It is also hooked up to my second dvr. On the other side of my basement I have a 73 inch mits diamond tv that is hooked to my ps3 and dvr with my 7.2 surround setup. with my 5970 and the eyefinity I have not touched the ps3 for gaming since I got eyefinity running right. It is the best thing to happen to gaming since 3d accelerated graphics came along.
My feeling all the way...
I have gone from a 52" DLP and a 40" LCD to my IPS Eyefinity setup and have NOT looked back since! Once you experience the immersion of the 3 monitors, it's VERY difficult to go back to the "blinders" type feel of a single monitor- which is how it felt when I disabled my side monitors to see how it felt after an evening of triple-monitor-gaming bliss.
As a side note, large, single displays DO of course have their place. Mainly, for games that don't support triple monitor properly, or games that are just TOO much for the ultra-resolutions that Eye provides (Crysis/WH, for example.). Actually, I will most likely add a 30" LCD in the near future to my Eyfinity setup- if for no other reason, to have TV/Video on while I work on my triple-monitor-desktop. (and for Crysis- yes, I DO still like that game. :doh )
So in a PERFECT world, I'd have both- but choosing, I'd rock the triple setup, hands down! :rockout