VLC is so easy to use, even for a 2 yr old.
My little rugrat prefers VLC for playing DVD's and files off the network.
Here's a short video clip:
http://www.youtube.com/watch?v=N_fI9eA8f7c
and a longer one where he's messing with the video distortion features:
http://www.youtube.com/watch?v=eGYnkjH-CnY
~kyoorius