Ahh, I got a 30" Apple Cinema Display. It was used, but still had about a year and a half left of Applecare, and the guy was only selling it for $750. That was back when ACDs were still going for well over a grand, so it was a hell of a deal to me.
Even though the 30" ACD lacks inputs, and might seem pretty dated compared to other monitors, I love it for the color, and real estate, so for my needs, it does everything wonderfully. Of course, I'd never pay the $1800 that Apple charges for it brand new right now.
I'd say some other good options are the Dell 3007 or 3008. Samsung and HP make some supposedly good 30"ers as well, but I've only used the Dells at school. From my experience, the Dells are pretty nice. They have good panels, and a bunch of inputs, so I'd look into those if you really want a larger monitor. I've seen people get them for as cheap as $700-ish from Dell Outlet.
Another monitor I've been reading about that really has caught my interest is the Dell U2711. It's a bit expensive, but from what I've read, it's very impressive. So that may be worth looking into as well for one of your options.
Most importantly, make sure you can drive a 30" monitor. Most Macs with discrete GPUs should have a dual-link DVI output, or if you have displayport, you'll need an adapter. Otherwise, you won't get the full resolution, which is the whole point of having a 30" beast. The reason I thought I'd mention it was because in my search for a new laptop (non-Apple), the model I want only has an HDMI and VGA output, so I would not be able to use my 30" with it. Guess that's why I'll always have my old MBP on hand.
But I'd definitely say go for it, and move up to a larger monitor. You'll never look back, and you might even wonder why you never upgraded sooner. Just make a list of your options, research each one, decide on the one that best suits your needs, search around for a deal, and finally pull the trigger and enjoy!