The big thing about the LS40A23W is that it's well, big. At 40", Samsung hypes it as the world's largest LCD television. If you want to go bigger you could always look at a Plasma model, but in LCD terms if you're looking to impress all and sundry the LS40A23W is the way to go.
Upside: In LCD terms, the LS40A23W is huge. It employs Samsung's Digital Natural Image Engine, which, in theory, should give it realistic images on an LCD panel with little of the overlay and blurring problems that tend to affect lesser LCD screens. It's HDTV ready as well as XGA capable if all you want is the world's biggest desktop monitor.
Downside: The biggest current downside to any LCD monitor is the price; they just can't -- at the time of writing -- compare to Plasma models in terms of bang for your buck. As such, expect the LS40A23W to make a hefty hole in your wallet when you lug it out of the store. At the time of writing, other manufacturers were busy preparing even bigger LCD screens, so don't expect the LS40A23W's screen size advantage to last too much longer.
Outlook: LCD monitors are still in the catchup position compared to their Plasma brethren, and while there are pricing hurdles to overcome, they're getting better, and in the case of the LS40A23W, bigger all the time.