hi matthew,
I have the 36ZD26P (36" non-DD version). The TV has three scart sockets (EXT1-3) and a set of component inputs (EXT4). I currently have my sky digital going into EXT1 (the only scart with RGB enabled) and my sony DVD into EXT2 via S-video. The latter of these is only temporary, I'm waiting for my 5m component cable to be delivered and then I'll change over to that.
AFAIK the scarts for EXT2 and EXT3 both take s-video, you just have to set them to do this in one of the menus. If you don't you just get a black and white picture.
I don't know what the sound is like on the DD set, but if I were you I'd save the money from the difference in cost of the DD version over the non-DD one (about £300 i think), and buy a separate amp and speakers, I'm sure that for a bit extra money you could get a LOT better sound. Seen as your sony has a built in decoder you might even get away with an older, cheaper, non-DD amp that has 6-channel inputs (older yamaha ones had these and were very good quality for the money).
Of course this means having loads more boxes in the room and probably more intrusive cabling, so might not be what you want.
Regards,
Owain