Coinops on original xbox, over 6000 classic arcade games - favourite is Galaga.
I've been playing with my old original xbox a bit lately. Actually I have 3 of them in the shed. Started when I was looking for something to stream digital music from a network storage drive, and I loaded a newer version of XBMC (now XBMC4XBOX) onto one of them. reformatted the drives and loaded all the old game discs back on the HDD. I realised that I hadn't even played some of them, so been playing all the old shootemups. They are still slow at scanning the music into the library though, about 24hrs for 2950 albums
Was going to try using the PS3 for the shed music, but the fan is so bloody noisy in them. Plus, unless you have an original that hasn't had firmware upgraded, and you can possibly run Linux on it, the music interface is absolute crap.
Using a Raspberry Pi for music streaming in the house, loaded with either Volumio or Rune music players.