I disagree with Frenchie...
The question is, as I see it:
Spend a ton on one, kickass monitor
Spend a decent amount on 2 monitors
(Note than in the end, you're still spending a lot. A $100 monitor is cheaper than a kick ass $180, but not when you buy 2 of them)
The pros for buying a single monitor, according to Frenchie are:
First of all, you can get a pretty nice monitor for under 200 bucks, let alone 280. And that monitor he chose is expensive because it has a BUILT IN WEBCAM and BUILT IN SPEAKERS, both of which are low quality, and jack up the price unnecessarily.
My tip is to buy a monitor that is barebone, no speakers, no webcam. That way you can upgrade to better ones, without being stuck with the first pair that came with it. Eg, lets say that you're tired of that 1.3mega pixel camera 2 years from now, and want something better? Have fun spending more money on another webcam, that you attach over the built in one....same for speakers.
Also, getting a dual monitor set up is always a great, productive choice. It offers way more room, and great for multitasking...take it from me =D
You can take frenchies advice and buy a single 24" monitor for $280, or:
Dual Monitors: $189each