DivX was used a lot when Divx Networks was running stage6 video website. However, if we're talking about torrent movies and what not, the de facto codec has been xvid for a looong time.
XviD is a MPEG4-ASP codec, while h264 is a MPEG4-AVC. For details on these differences I recommend reading on doom9.org forums since you will find a great number of discussions on the topic as well as a lot of encode experts.
In short, x264 provides better quality at lower size, but requires more computing power to be decoded. In addition, most recent DVD players will play DVDs (duh) as well as xvid encoded content, but not x264 - unless if you're talking about devices such as the popcorn hour, WD live tv etc, but then again they don't exactly classify as dvd players since they read content off the network/local disk.
Due to it's efficiency, x264 is the codec used for HD content. It's also noteworthy that there are a lot of devices relying on hardware to decode x264, thus making it faster. It also proves a certain dominance. Which in this case, is a bad thing considering h264 is not patent free, and you may end up being charged high sums of money after the MPEG-LA decides h264 usage is no longer available free of charge.