Help for new htpc and server

I have built a pc before however have not ventured into the standalone server or htpc area. I would be grateful for advice on parts and components and also any know-how one would like to lend

I was thinking about creating an htpc to connect to my av setup and the server to hold the media files and possibly to act as a standalone torrent machine. I would like the option to add bluray to the htpc eventually however am not particularly fussed about including that initially. I will need to connect the htpc via hdmi to the flat screen and have the option to stream audio either via optical/coax out (I would say via analogue but do not have them spare on my receiver). Sometimes I wonder if it is better to do external dac however I am not aware of any good multichannel standalone dacs. I currently have sky hd and therefore using pvr is not important currently but space to add tuners later may be useful. I currently have an ARCAM Amp and DVD player in silver hence looking for something to blend in with such woudl be great.

My server will need to be wireless I think. At the moment I have a pc upstairs connected via router which feeds off the internal wiring. I do have access to a spare wireless router netgear 834gt an I suppose an option may be to use one 2 routers and somehow link them and then wire the server to the router. I would like the server to work a standalone torrent device and therefore leave my upstairs PC to do the bulk of any video editing/ encoding etc.
I realise wireless is a slower option and therfore for large files (e.g.) it may be necessary to have the ability to shift them to the HDD of the htpc on a temp basis to achieve a stable picture to watch.

Your help would be appreciated