I recently purchased two 24" monitors from dell and they are awesome! So that makes 2 24's and 2 21's! In screen real estate terms, this could be counted in square footage rather than pixels
The two on the sides are connected to one computer that I use for email and music and the center monitors are part of another computer that I use for work and web. You can also see that they are all turned vertical. That's great for my artwork (which is vertical 90% of the time) and it's great for websites which are typically longer than they are wide. The graphics cards are new also. My old ones didn't allow monitor rotation.

CONS (if any): Horizontal images aren't as fun to work on and remembering which mouse and keyboard goes where gets confusing. I'm looking into applications like Syndergy that allow one muse and keyboard to control both computers.
I think square monitors would be the best but this will do.

LIST:
1. Microsoft Outlook - I'd be completely lost without it! It's dark because I have all the windows turned dark on that computer so that it doesn't distract me while I'm working on the main computer. I also have both computers set to a 5 minute screen saver response time - it's not like I'm looking at all four at the same time.

2. Rhapsody - love it!! If you don't know about Rhapsody it's a streaming music program that allows you to play almost any song at any time for $10 a month.

3. My website (no I don't always leave it open, I just wanted to put it in there)

4. Winamp - playing the music I have on my hard drive. Even though I used to design winamp skins for Warner Brothers and other big companies, I still use the classic version (probably because I'm sick of them)!

5.DeviantArt of course! This I do leave open all the time!

6. My main monitor for work. Candy Girl [link] at 50%

7. Old high school drawings. Other than that my walls are pretty bare. They say you are more creative in a gray room.

8. Summer camp group photo.

9. Old TV - my next purchase will be a nice TV Tuner card that will run on the right monitor.

10. Altec Lansing speakers - In my will it says these go in the coffin with me!!!

11. Note pad, full of scribbles and notes. I used to write on loose paper and I would always misplace it.

12. My mouses - no more than $20 each at the store. The one on the right created the majority of the work you see in my gallery.

13. Parmesan Goldfish - one of my favorite foods!

14. There's a pen somewhere down there for my tablet, which I almost never use. *yes people, I use a mouse!

15. Like I said the two keyboards can get confusing.

16. $10 headphones that I've had for years and still sound great.

NOT PICTURED (but usually there):
Sushi trays
Cell phone
Water bottles and sometimes Coke or Diet Dr. Pepper
Crumbs (yes, I cleaned up a little for you to see)

enjoy!