i'm gonna build a jukebox next should be exactly the same as a pin i just have to figure out what program to use (windows media player?) how to get flashing lights to work etc and how to turn them on and off when the computer turns on and off

I use XBMC - it does the whole deal for me. Movies, TV, music, etc. I have a 4 x 4 HDMI switch that can send output from up to 4 devices to 1 or more of the 4 screens (PS3 to the small TV, Wii to the 50" plasma, XBMC to the projector and second small TV, etc). I use a Logitech Harmony remote with the RF transmitted/receiver, so it works anywhere in the room at any screen.
I haven't done lights yet, but for music, you're essentially talking about a light organ, which LEDBlinky will do for you if you have a PACDrive or LEDWiz connected to some lights. It'll use the music to flash and fade the lights to the sound. If you're creative about the placement of your lighting, you can turn your basement into a dance club. For movies, I'd have the lights come on low, just for ambiance.
The only thing I'd like is a touch screen somewhere to control the music, which is doable, but it'd mean custom programming for now - but the XBMC software does have an interface that can be controlled via HTTP requests, so it's entirely possible to write a touch interface and have it send commands to the XBMC machine to execute.
I do like that I don't have to have a separate box in the room for music, though. Just use the already existing screens.