S!
Well, I thought about it quite long, and then decided to go for the one big one. I just couldn't accept the idea of having the bezels between the monitors interrupting my view.
Got this LG W3000H 30" monitor about 4 years ago, and haven't regretted a bit.
The 2560x1600 native resolution is the bomb. So much desktop space
.. And no need to use antialiasing in games as the pixel size is so small you really can't see the jaggies.. well at least I can't, and I have perfect vision.
The biggest con is the price... ~1000 euros currently in some finnish shops. But I thought: I won't be needing a new monitor in at least 10 years, and this is the single most important piece of my simulator setup... so what the heck.. it'll only sting once
And.. having head tracking will make the three monitor setups a bit obsolete, I would think. Of course they add to peripheral vision, but I would guess that the help would be quite vaning. Three monitor setup guys should comment on that one