Is it worth switching from 5.1 to 7.1

[Lightning Steve]

Not long ago I picked up a Sony STR-DG520, the price was good, it did digital, and the Denon it replaced was old and only did PL I, (plus the 4 remotes I went through didn't work). At the time I didn't see the need for a reciever that would do HD sound as I had a crappy TV, and wasn't going to be getting a BD player. Well.....
I now have a better TV (32" Plasma) and a PS3. But can't play HD sound, which bugs me. So I've been thinking of going to a 7.1 system. Now the room this is all in is small (bedroom size) and I will still only be using my PSB 5.1 speakers (because of room size I don't think I can really install two more speaker behind the couch as it's already against the wall).
So my reasons for the switch would only be to "get" HD sound, but will there really be any differance with a 5.1 speaker set up? So I can accually use HDMI cables (it will simplify things), the 520 just does "pass through" which is pointless.
I realize I will not be utilizing the reciever for all that it has but I am (have been for 6 years,lol) building a larger HT room down stairs and will be able to make better use of it there, but at the rate I'm going we will probably have Holodecks and aural-implants by then.
But is it worth the switch to 7.1 now, will I really notice any sound differance playing HD audio on a 5.1? Just looking at the Sony 720 (I know alot don't like Sony for some reason but the price is far lower than most others) or a Yamaha 7.2 system (forget the mod #) that's a couple hundred more than the Sony. Or should I just be happy with what I have and show some patients and wait till I get the room down stairs finished?

 

[Exit]

I've got a 5.1 setup, but my receiver can go to 7.1, and I already have two more speakers for a 7.1 setup (I am using them for front presence channels on my Yamaha receiver). The decision to go to 7.1 over 5.1 in some part depends on your room size and layout. I have my speakers in a great room so I effectively have no side walls. I have the surrounds on my back wall. They are placed about six feet apart. There seems little point in putting two more speakers in between the existing surrounds because of the close surround speakers. So I suspect this would be the case for 7.1 in a bedroom. I think the two 7.1 surround speakers really come into play in larger rooms where there is a much wider spacing between the surround speakers. Then the two 7.1 speakers can fill in the soundfield between the 5.1 surrounds. Under the proper conditions, someone else can speak to whether there is a big sonic improvement or not to justify the added cost.

 

[Geno]

I have a 7.1 setup, and my rear channels are ceiling mounted. Frankly, I think they're not necessary or noticeable, but, like the previous poster said, if your room is big enough it may be worthwhile.