just remember NO SPACESHIPS!! everyone hates them 'cause they have to look at them all day.

a good demo reel (burned cd works better unless specified otherwise...don't use funky compression codecs) should be about 2-3 minutes long, with your very best work first. after that, you can include whatever you think demonstrates your skills, even if it's bouncing balls. if you worked on a team project, give credit where it's due...and this thing is only as good as the "worst" piece of work, so choose carefully when you're ready to make it and send it out!

if you have an original concept (i dunno, purple elephants playing rugby...a traitorous penguin advertising microsoft products, statues that make less than flattering comments about the tourists posing in front of them), definitely put that in. oh, and animating a human character is a big bonus. if you're looking for work in television, games or film, include specific work. i.e. low-poly models for a game.

good luck!