My idea was to use my computer to control the LEDs. Because I was thinking of using tri-color (RBG) I could use my computer to change how bright they are and then illuminate my pc in any color.

(in a good way) I think I used “controller” in a bad way, I wanted to use my PC to control the LEDs. That way I could fade them any way I would like and do pretty much any thing. I could also have the audio synchronize up to the colors in any why I would like if I could use a programming langue on my computer to control it.
Basically I’m looking for some hardware what I can hook up to my PC and control several outputs.