PS3 and Surround Sound

[Terbinator]

I've been thinking about picking a surround sound kit up for some time, one that supports optical in for the real deal so to speak such as the Z-5500's from Logitech, however something has been bothering me.

If i were to buy said kit, or any kit that supports Dolby Digital and DTS, what format would Blu-Ray movies play in? Im under the impression that they use Dolby True HD and DTS HD audio codecs in comparison to normal DTS and Dolby Digital - so would i only get stereo sound if im using non-HD reciever, or any sound at all ???

Any suggestions for other kits i could look at would also be welcome but preferbly under £250.

[Lowe]

The PS3 will down mix it to whatever your speakers can play. I don't have an HD receiver, however have never had a problem with my PS3, it tends to down mix to either normal DD or DTS.

[wazi]

ive got a z-5500 connected to mines and it is AWSOME !!!!
normally watch xvid/dvd/ bbrips and the sound is phenomenal
dont think u can match the sound for monies , u will pay double and a new format will come out !!!
money money money