Hi,
I've got a Dell 24" monitor and I find it very good for games. Great brightness, good contrast and color, fantastic peripheral viewing angles and plenty of extra inputs for your other AV equipment, as well as a USB hub for your gaming joysticks and things if you have them.
The only issue with gaming is that my GPU isn't really powerful enough to drive newer games smoothly at the native and maximum resolution of 1920x1200. Older games run fine at this resolution (such as UT2004, and Morrowind at 1600x1200). But the newer games still look alright at low resolution on this monitor. I run Half-Life 2 and Oblivion at 1280x720 so my video card can cope and onscreen the image looks just a little "softened", but it's still really good. If your game has any fun factor, you won't be bothered by image softness at lower than native resolution (this would happen on any LCD).
I'm not a graphics artist myself, but my understanding is that no LCD reproduces colours onscreen as accurately as a good CRT monitor.
Three monitors?! If you've got that kind of funds to spend - get a 24" monitor first, or even get a 30". From what I've heard, I wouldn't bother going for Apple over Dell. The Apple 30" has inferior brightness, inferior contrast, an ergonomically MUCH LESS functional stand, the same response time, fewer extras (fewer USB ports and no card reader), and SUPERIOR aesthetics (though this is debatable) compared to Dell's 30" monitor.
Given all that, there's really little reason to pay a 25% premium for Apple's monitor unless you're a real fashionista. But if you are going to do graphics work, I would consider stand ergonomics (but if Apple's colour reproduction is better that might be a factor too) - actually I believe the actual LCD panel in both Apple and Dell's 30" monitors are made by the same manufacturer (Samsung I think, not sure) - so colour reproduction is possibly similar.
One other thing about the 30" monitor from Dell, is that most reviewers agree that though it's good, and a heap bigger than the 24" model, the image quality of the 24" Dell is a lot superior (brightness, contrast, response and all that again.)
Another other thing is the price premium of the 30" over the 24" - but that's a personal decision. My personal thoughts are that I wish I could have a 30" monitor, but not at the cost of sacrificing the image quality of my 24" monitor ... and not at the price premium either - 30" Dell costs almost twice the 24" Dell before you even think about Apple.
I used to want dual monitors just for überness, but now I think one big monitor - definitely all the way.
Yet another thing with the gaming. With Dell's 24" (NOT with the 30") if you game at a lower resolution and you don't like the stretched picture, you can set it to display the resolution at 1:1, so only the pixels in the middle of the screen get used with a wide black letterbox effect on both sides and top and bottom. Waste of a big monitor! I'd rather the image fill the screen, but the option is there if you want the sharpness at lower res.
No I don't work for Dell.