Unless you are a programmer or graphic designer, a widescreen is probably better than dual screen, or better yet two wide screens
When using two screens keep in mind that playing a movie or a game only one screen will be used.
LCD monitors come in set resolutions and larger does mean more pixels (which means more usable area), but they usually go up in jumps.. so in widescreen monitors they start at 1440 x 900 for 17" and 19" ones.. 20" to 22" ones are usually 1680 x 1050.. 24" to 27" usually 1920 x 1200 (or sometimes 1920x1080), and then 30" is 2560 x 1600.
So between monitors with the same resolution, bigger monitors will just mean bigger pixels, though usually not enough so to make the image "worse", but it's a subjective thing.
I usually suggest getting monitors from places like FS or BB just because you can return it if you don't like it and try something else, but usually they don't have the monitors that I like, but I'm picky.
Something like that Samsung is not bad, personally since I game and do some graphics work I won't go for a monitor like that since the image quality is going to be not as good as monitors that use a superior technology, but it always depends on what you are doing with it.. many people are fine with that kind of monitor.
Help buying a new monitor
