You might want to check out Yamaha's new YSP-1 "Digital Sound Projector".
This is a single amplifier/speaker component that creates 5 channel sound (you still need a separate subwoofer to make it 5.1) by (I'm oversimplifying) "beam-steering" five audio channels to different points in the room, thereby creating front left and right, center, left surround and right surround channels. You need a fairly normal size and shape room for this to work right, in that the steered audio needs walls to bounce off of. From what I have read/heard, the creation of a near-5.1 sound experience is pretty good. One warning is that a demo of this product at an audio/video store might not do it justice, depending on the room set-up at the store, and whether the unit was set up right. It is not cheap (I think MSRP is in the $1,400 range, roughly), but given that the unit contains all of the speakers for the system except the sub, and also has its own built-in amps, it is worth looking into for rooms where it is just too difficult to do a regular 5.1 (or more) setup.
You might also look at some form of wireless speaker approach for the surrounds, if getting wires to them was the main obstacle. The "cheap and dirty" approach of just leaving out the surrounds (i.e., front and center channel only) is not the end of the world, either. For that matter, neither is 2-ch. stereo through a high-quality system. Either will be more satisfying than listening to the TV's speakers, even if not as "enveloping".
