I'm thinking of basing this around a mini instead of an Apple TV as it's more flexible (IMHO). I'd like to be able to play DVD's, listen to music, look at my pictures and download TV, films and music from itunes. However the ATV has more in the way of output than the mini, so it's not a given.
I'd like to be able to watch satellite TV, on a 1080p HD TV and a home cinema sound system and send music to some seriously decent speakers. I'll be pulling the internal HDD on the mini and replacing it with a bigger 250 GB drive and compliment it with a 500GB external drive with a mini like form factor. I need to be able to record TV to the hard drive and have the mini act like a PVR.
Not vital but on the wish list is to be able to share media to other Macs in the house via either wifi or wired (not sure which yet). I'm also thinking of maybe having the main media library on some kind of network storage rather than directly on the mini if this makes sharing easier. I'll be backing all the data up too, via a NAS.
So, feel free to jump in with comments etc. I'll be checking back in with my ideas for the various components (speakers etc) but I know people here will have their own ideas.
For example what about a slingbox? I know they major on remote content serving but would they work just as well on a LAN?