I had my lcd mounted above my fireplace, but would possibly like to add additional sound. The issue is there is no way to logically hook up a receiver or for that matter add any equipment without making it appear tacky due to wires being exposed.

There are of course the flush-mounted speakers. On-wall speakers are an option, but don't look as good.
The Yamaha sound bar can sound a lot better than you might think, but isn't hugely pretty.
Either way, it'll cost you a fair chunk in installation costs if you don't do it yourself.

Otherwise you could get great sound from placing two floorstanders (one either side of the fireplace). It will be stereo sound instead of surround sound, but with a half-decent amp it'll probably sound (provided your speakers don't come from a white van) far better than any in-wall or on-wall option simply because it will sound a whole lot more real and dynamic.

Paradigm 330's side and above Plasma - all built into the walls, wiring is all hidden.
Even if you arent building a whole room from scratch-fishing cable thru walls rates a 1 on a 1-10 scale of difficulty.

is too high to be mounted over a fireplace.

In-wall speakers have come a long way and many actually sound great, but Master bedroom is on the other side of the wall from TV in livingroom.

In-walls project a lot of sound to the rooms on the other side of wall. In-walls with sealed enclosures and/or insulation help, but some sound transmission is inevitable.

Like everything else, it's a matter of taste. Go with what makes you happy.

Here's a link to a previous post on my install...<ul><li><a href="http://forums.audiworld.com/htelect/msgs/18967.phtml">DIY install</a></li></ul>