Does anybody know of any linux video players that play Xvid and DIVX format movies? I've gone through the trouble to install the Xvid codec to absolutely no effect. Any pointers in this section?

Pretty much any.
MPlayer, Xine, VideoLan Client, Totem.

Many linux players work differently to windows, they have codecs built-in (not sure about xine and totem).

mplayer plays divx through the prized libavcodec so its not necessary or recommended to install the divx codec. I prefer mplayer but some like xine.

Totem is just a frontend of xine, like Kaffein.

I'm using Kaffeine as my player. I installed all the codecs and everything to allow me to play DVD's, and in turn I can play QuickTime, DivX, etc...

What distro. of Linux are u using?

I use mplayer, and I use gmplayer as a frontend.