Home Cinema Virgin!

I will try to keep this short but I look to your vast knowledge and input in me achieving my dream

New build house (build start 15/08/05) with a dedicated room for HC measuring 5m x 2.4m with one window on the shorter length.

Equipment chosen so far:-
Plasma - Panasonic Viera TH-50-PV500
Amplifier - Yamaha RX-V4600
DVD - Yamaha DVD-S2500
Sky - Will wait for HD box of tricks
PS3 - When available

Equipment I need advise on:-
Speakers - Preferably flush in-wall mounted 7.1 inc height off floor
Remote - a mid range unit
Cables - no idea what and how many etc
Wall Plates - what and where from
Projector - Motorised from ceiling - Infocus?
Screen - motorised
Soundproofing

My budget would be 5-8k total for the room which I will be the VAT reclaimed from the build. My main worry is I will have to put in the infrastucture i.e sockets, cables, lighting etc before I can purchase the hardware and this will need to be spot on. Any techies is the Warrington (Cheshire) area that I can buddy up with? Your input would be most appreciated to make this as smooth as possible.