I've got a PS3 which has a dedicated 400Gb internal drive for purely games, music and photo storage, it also has a 250Gb hard drive attached to it which is purely used to store movies and a third 320Gb hard drive which stores TV programs.
Obviously i use it for Blurays, DVDs and the aforementioned mass of videos. Because it's also wired to to two separate amplifiers (one optical for 5.0 surround and one analogue) it's used to listen to music and because i get rather bored of the Earth visualisation i like having a slide-show of images playing while the music is.
Also the BBC iPlayer and 4OD (which is beyond useless) and i have direct links to the Escapist videos that i like.
and occasionally i'm known to play games on it. Despite what people say, it's an incredibly useful media centre.