It's going to replace this piece of crap desk:
http://i247.photobucket.com/albums/gg151/Zellio2008/SDC11174.jpg
(the yellow thing obviously)
It'll be my workstation in my room, next two my triple screen eyefinity setup. I could put the quad monitor setup to the right of the laptop, or put 6 monitors above the laptop (They'll have to be decently high though, which could be an issue with line of sight).
Here is on of the types of monitor stands I'm looking at:
http://www.newegg.com/Product/Product.aspx?Item=N82E16824994004&cm_re=quad_monitor-_-24-994-004-_-Product

Why so many monitors? Once you fill your FoV, I don't see the benefit.
What does this setup need to do for you?

I'd say neither. If for gaming, and odd number in both directions is needed if you don't want your crosshair (or whatever's in the middle of the screen) to be split between two monitors (also, for gaming you often need to get the computer to treat them all as a single huge screen, since games seldom support multi-monitor setups). Splitting is fine if on the side, but your attention more often than not is at the center of the game area, an even number of screens in height or width distorts that attention as you need to focus on two points at the same time (even if they're just a couple centimetres apart it's instantly much harder to focus in them as one since they SHOULD ideally be almost the same point).
If not for gaming... go with whatever you can afford and you think you may need/want.

Right now, I am typing this on my current 3 monitor workstation. here is an early pic before I had the touchscreen operational:
http://i247.photobucket.com/albums/gg151/Zellio2008/Sdc11007.jpg
I use the 15" touchscreen as a program launch panel. I use the 24" in portrait for things like forums, word, excel, etc. I use the 23" in landscape for general things.
I have attached an image showing how I use the 15" touchscreen.
I have cleared off the area with scissors to add a 7" portable tv. Now I can keep track of things like weather as well as have something to take with me.
You ask me, 'why do I need so many monitors'? In turn I ask, why can't the average person multitask efficiently?
I can't speak for the average person, but more monitors=better productivity for me.

I'm not asking why you want many monitors, I do too, but I'm not sure I can effectively use more than three. I have two for my main desktop at the moment.

Well I can. Although I'm not totally sure if 6 would be all that more effective than 4.

Go for the geek points/e-peen then, get whatever you can afford just for the surprise of others entering your room.

Actually it would simply send my geek points to over 9000, as anybody coming to my room gets surprised...
... By my cable mangement and old geek crap.
http://i247.photobucket.com/albums/gg151/Zellio2008/Sdc11173.jpg
My room tv and ps3.
http://i247.photobucket.com/albums/gg151/Zellio2008/SDC11175.jpg
My bunched in collection of old games.
http://i247.photobucket.com/albums/gg151/Zellio2008/Sdc11172.jpg
Tons of old games.
http://i247.photobucket.com/albums/gg151/Zellio2008/Sdc11182.jpg
http://i247.photobucket.com/albums/gg151/Zellio2008/Sdc11177.jpg
My alarm has a tendancy to keep you up at night....
http://i247.photobucket.com/albums/gg151/Zellio2008/Sdc11171.jpg
Can you spot the surprise?
http://i247.photobucket.com/albums/gg151/Zellio2008/Sdc11181.jpg
It's Cable the stuffed cable management guard dog! He helps keep my 3 foot tall pile of cables from falling over.

He can have 6 monitors and pretend he's a naval commander.

This is for real work and not play.
The rest of my room is meant for that (play).

Oh well, I've made my case twice (get the biggest you can). It's up to the others to talk you away from spending this year's paycheck on monitors.

Yes, you have.. E-peen geek points? As I noted, I don't need the geek points, I have a real reason for needing multiple monitors, and I can actually put them to good use.

I did have another as well, but you shot that down too. Is it my fault that I look on anything more than the extreme bare necessities (food, roof, bed) as toys?
:-P

Well, toys/funstuff/not necessities. Yes, anything not necessary to survive. My several computers are toys, though I use them for work as it is today I could as well be a dairy farmer and not have any real use for them. I want better and more fun toys though, so I upgrade every once in a while and get more monitors because that makes my toy more fun to play with. I also walk to work because I like walking, I could take the bus or bicycle as well, but why would I (don't have a driver's license, don't see the need and it's nothing I desire enough to go through the trudge of getting one).
Of course, each person has their own definition of the word "need", anything you don't need is you do or get because you somehow get something out of it (you feel good for buying food for your friend who's a bit short of money at the moment, even if the food itself doesn't benefit you). The bank accountants could work with pen and paper, but the introduction of computers has made some people think that society "needs" to go faster, and in effect the accountants "need" the computers to keep up with the faked "need" of speed.