multimedia solution

I have a desktop, laptop, router, tv and amp. I want to be able to access ripped tv and iplayer files on my desktop, on my tv wirelessly. Or eliminate the Desktop, get an external harddrive/media streamer, transfer my divX/Xvid files to it and play them on my tv and amp. If I eliminated the desktop I would want to download directly onto external harddrive/streamer via laptop operating system (I use ubuntu) Is this feasible?
someone suggested a PS3 could be the answer but as I'm not into games i wonder if theres a better option out there. I thought about an external HD connected to laptop and connecting via s-video laptop to tv but this is going result in slow stuttery playback.