uhh well some demos ive kept for a while already. since i download them, play them, then delete them.
ive got Top Spin 3, Warhawk, The Bigs 2. I keep the demos that you can play for a long time. I had fifa 09, UFC 09 until i bought them. I delete demos like batman, infamous since you do the same thing and its always the same, so it gets boring.