FWIW...
I've owned a Nook Color Tablet for less than 48 hours, but so far, it's playing everything that I ask it to play. Instead of loading movies on it, I play videos using my Buffalo NAS which holds about 1.8 TB of video. I've tried several players, but only MX Player plays everything without complaint. I use ES Explorer to browse the files on the NAS, then MX Player to play them.
Don't be afraid to root your NTC. It took me less than five minutes to root my NCT using in the instructions at
How to root the Nook Tablet ? Cell Phones & Mobile Device Technology News & Updates | Geek.com. After you root it, you'll want to install a home screen alternative (not a replacement, per se, since you can't kill B&N's native home screen) and install Homecatcher so that you can always get to your homescreen. Once, there, install your favorite apps and you'll have a fantastic little video player.