although some of the divx movies i downloaded looks pretty good, im not going to put down $400 on a player just so i can play them without a compter. depending on who encoded it and what encoder was used, the picture quality on some movies is just crap while others can surpass the quality of vhs and getting pretty close to dvd. the ones that have some kind of corruption in them that makes the video and audio become out of sync are a real b!t#@. you gotta stop the movie, fast forward from the beginning to the point after the corruption so that it doesnt screw it up again.
like all the other members have said, using the $400 to build a computer made specifically to play those movies is a much better investment. you get the functionality of a computer and a dvd/vcd/divx video player as well (depending on whether you get a dvd-rom or cd-rom).