Have you searched around on the forums here? There's several threads about just this topic.
I know a lot of people recommend Freebox for jukebox software. Personally, I like JRiver media center, it's really good for media organization/tagging etc, and it does have a very nice interface for home theater uses, but it costs a little money.
Then there's something called Media Monkey that looks pretty dang good for a free app, but I've never installed it.
But there's a lot more options floating around too