I was kind of considering this issue as well - You pick an ultimate goal/dream, then you come back down to reality of how far your wallet can take you.
3 x 30" 2560x1600 monitors would be a dream with a Tri/Quad SLI 3GB GTX 580 setup in portrait.
Alternatively, I looked toward a thin bezel 1920x1200 16:10 monitor (they're so much better than 1080p 16:9 ones - my preference) - But it's kind of like just repeating my monitor 2 more times on either and increasing the FOV. This is something I've yet to experience, so I cannot comment on it, hence my interest and curiosity into that subject.
I have, however, used a 27" Apple @ 2560x1440 (16:9), the U2711 at the same resolution, as well as the 3008WFP. Productivity and real estate transforms the entire experience when you're on your desktop, surfing the web, benchmarking, doing work, multitasking all within one screen - and it beats productivity on 2 screens (I have 2x 20inch dell 1600x1200 screens at work and I can honestly say that the hugely superior 1600p/1440p screens are night and day - they make me smile

)
I can't comment on gaming, but my preconceived perspective is the bezel issue - but most argue that the bezels seem to 'fade away' after minutes of the incredible immersion that surround/eyefinity provides. Like a couple others in this post, maybe you need to try it to find out - i know it's tough, but how far are you willing to pursue your interest? Then again, we could be the types that would rather evade the effort of trial only to find out a larger monitor is preference of the two, and the trouble of selling unwanted equipment is prevented if you are risk averse.
Another thing to consider is that surround 3 x 1080p will be pushing over 6 megapixels which is even more than a 30" 2560x1600 setup that is about 4+ megapixels (effectively a ~33% performance dip if you moved from 2560x1600 to 1920x1080x3 [[ or a 66% performance dip moving from a single 1080p to surround 3x1080p]] - sorry i had to add that to better envisage the inevitable processing power upgrade requirement) - no point dialing down settings to the lower end while using a 3 x monitor setup!
I'm very much envious that Palit released the 2GB version of the GTX 560 TI but the GTX 570 is cursed with only 1280MB while the GTX 580 gets 3GB - I guess the middle child is always left out. For me, my plan to upgrade my monitor after this made me thoroughly consider vram limitations - and this was discussed quite thoroughly in another thread I started about a month ago - and Brett, amongst others helped establish that a few of the top current games now will definitely eat into 1GB+ vram territory at resolutions of 2560x1440 and above (and going surround means you will need the headroom). This brings up another point that leads to AMD cards being an optimal choice due to a larger variety of cards they offer with 2GB of vram.
On the nvidia side of things, only the Palit GTX 560 has 2GB, the GTX 580 has 1.5GB and on Palit/Gainward/EVGA/ they've released 3GB versions of the GTX 580. so that's 3 cards (only made due to variants) with very large price and performance disparities offered by nvidia.
Hope I'm not dawning too much bad news onto you - but the point is that a fair amount of things have to be considered. Rumours of Kepler based GPUs scheduled for Q4 release (assumed 6xx series nvidia cards) make me hope that nvidia gets smart and slaps on more memory onto their reference cards because that is a strong offering that AMD has over nVidia at the moment (with the minor exception of non-reference cards).
-Bleah