I would say that the best single display is definitely going to be a 30" LCD. The Dell is $2,199, so that's in your budget.
If you're going to go with more than one display, though, you have to think carefully about how you're going to use it. Given the distance that most people like to sit from their monitors, when you get anything bigger than 2 x 20" displays, that usually means you're turning your head at an uncomfortable angle or else having to swivel your chair just to look from one end of your desktop to the other.
I've had a setup for about 5 years with a 22" CRT and two rotated 15" LCDs on either side. It's pretty goofy, but if you're working with a lot of documents, it's nice to be able to have two web pages or documents open on either side of your main screen.
http://home.woh.rr.com/brettland/rad5/0720_desktop.jpg
If I were building something new, I would probably just get a 24" 1920x1200 LCD and then a 17" 1280x1024 LCD that rotates to a portrait display (I'd probably actually get two portrait displays for a similar setup to what I have now).
That, or else I'd just get two 20" 1600x1200 LCDs. Two identical screens seems a little more normal, but when actually using multiple displays I find that I really don't like it as much when there isn't a single primary display. Two identical screens strikes me about like looking out a nice big picture window with a pole in the middle. I'd prefer to have three of them, so I'm looking straight into one of them, but then your desktop is just massive, and you find yourself putting single documens on the left/right screens, at which point you'd be better off having rotated portrait displays on the sides.
So, I'd get:
http://www.newegg.com/Product/Product.asp?Item=N82E16824001222
and two of these:
http://www.newegg.com/Product/Product.asp?Item=N82E16824116364
But the average person might be happier getting 2 or 3 regular 20-21" 1600x1200 displays if they wanted a bunch of monitors.