As for DivX being "lower quality" you obviously haven't seen a recent rip with automatic two-pass DivX v4.11 and mp3 at 192kbps.
It is indistinguishable from the DVD. And it barely fills an 80 min CD.
oh come on, you are either running really lousy dvd software, really lousy dvd player, really lousy tv, really lousy monitor to even make that comparison. I've encoded my fair share of two pass 3.11 or 4.12 divx with vrb mp3 so i don't have to jack up the audio that high which is a massive waste since video quality is so much more noticable then audio on a divx. There is NO comparison, especially for a 1 cd rip, even if you crank it to 730mb overburning. at 3 cd rips you start getting pretty nice results, but its just not worth it. your still degrading your original image by recompression, you lose your special featuers which sometimes really kick ass, you lose commentary(yes you can add a low bitrate track but it sounds like crap and eats into bitrate for the divx). some dvds have seamless branching, or links within the movie to special featuers etc, all gone with divx. with divx you end up with the functionality of SVHS ...good enough for little thieves, but not real quality at all. After all, its your time your wasting watching crap not worth even renting apparently
as for why buy? well if theres a great release of your favorite movie, thats a good reason. a lso if you can't find the dvd at those mega chain rentals.. which has piss poor selection. i still mostly rent
as for what divx might be good for? maybe hd dvd-rw unless they make a massive jump in capacity..course processing hdtv into hd divx would require some serious processing power. gah.