I've got a 450D and I use ICNR especially for timelapse/sequences.
Why? I don't want to disrupt my sequence timing by using up a timeslot for a dark, nor lose focus by pushing on the lens when I put the cap on. I end up halving my 'framerate' (so to speak), but at least they are regular and the camera is untouched between shots.
If someone can suggest how to take a dark without touching the camera I'll give manual darks a go
