Hi Bomadian,
I think it really depends on your house, your stereo setup and what you'd like to do.
For me, my imac sits with all my music dstairs. I have a pair of audioengine usa speakers on a shelf upstairs and a stereo/tv system dstairs (not near the imac). I have the airport express base station dstairs and the aiport express with itunes upstairs, connected to the speakers. nothing is connected to the stereo/tv dstairs, but once I get a widescreen TV, I'll get an appletv in a heartbeat. I was going to get another AE, but now that the appleTV does the same thing (and more)...no need.
The sounds upstairs is fantastic through the AE. I also use my macbook pro upstairs in the kitchen for a variety of things, one of which is to access the imac's library and direct music to the audioengine speakers.
as for the rest of the gear, I've had my stereo stuff for about 6 years which is pretty much prehistoric the way things change. I'm seeing tinier speakers (wireless too) and different stereo decks - ie. mine won't do HDMI so i'll need a new deck if i wanted the best with a new tv).
the best thing to do is also visit a local audio/video store...not a big box store, but a local store dedicated to purely home entertainment. they'll have some great setups and they might not have apple stuff, but the rest of the gear will be great to see and hear.
Hope that helps.
Cheers,
Keebler