Advice on purchase of AV amp & speakers on HTPC, PS3 setup

[chipo]

Hey all

Now I’m sure others will have similar setups but this place is pretty vast so after some advice on purchase on new Receiver / AMP & Speakers in home theatre setup. Here is current setup:

42" ATEC HD LCD with 2X scart, 1XHDMI and usual coax ports. Crap inbuilt speakers. Analogue 3.5 sound cable outputting to soundcard on HTPC
3X HDMI switching box
SKY+ with scart output to TV
PS3 with HDMI output
Wii with RCA or coax output (not the scart way!)
Shuttle HTPC with Blu-Ray/HDDVD with HDCP and 7.1 Creative Soundcard outputs to >
7.1 Creative Speakers with Sub

Ok so this all works ok however it's not great i'm sure the sound could be outputted better. The HTPC is acting almost as a amp however most of the sound is received via the TV from a 3.5 standard jack into line in on soundcard for sound from Sky, PS3, wii via the TV etc.. Only decent sound comes from the bluray and itunes playback from the PC itself however still don't think this is great. Also don't want to have the PC on to watch standard Sky or when playing PS3.

So my question is can I purchase a AV/AMP/RECIVER which will do all the legwork and output to a new decent set of speakers?

Also how will it receive sound from Sky, PS3 & HTPC? Can this be in a digital way. The PC itself has got a optical out as well as standard 3.5mm 7.1 outputs.

As far as picture goes currently the Sky runs direct to the TV via scart and the PS3 and PC run via a HDMI switching box to the HDMI input on the TV. Do any AV amps allow scart / HDMI connections to carry sound and video which output to 1 HDMI output? or do you have to connect sound via separate outputs on the devices such as optical sound out on PC and PS3?

I use PIP quite alot for using PC on the TV with Sky running in the top right, would this be affected at all.

Not sure if i'm making any sense, sorry for all the questions. If anyone has any advice also any good speaker setups (4, 5 large decent speakers to work in lounge) to work with the Amp. Models welcome. Total budget. £400 - £600

Cheers

Tim