Soundbars: flat, compact and easier to setup than even a home theater in a box setup. We're seeing a lot more of these speaker solutions in homes (and especially apartments). Some have even have integrated DVD players! Add on a subwoofer and you've got a decent sound system without the hassle of running wires and cables around the house...
Premium: CineMate 1SR by Bose
At $1499, this soundbar and subwoofer tandem is probably going to be more expensive than a brand new 46" LED panel. Admittedly, the Bose model is pretty sleek and connects directly to the HDTV without a receiver. Bose claims they've engineered this model so it can determine whether it' laying flat on a table, or mounted on a wall, for optimal audio performance (Bose is one of those brands that either instill total brand loyalty or total eye rolling, so take this claim as you may). The subwoofer is connected wireless, and produces a quasi-surround sound using audio reflection.
Other sound options are: