I just installed debian lenny on one of my computers and noticed when I installed the x server that it didn't generate a x.org.conf file (well, it did, but it was empty). If I don't remember it wrong I think I got automatically a xorg.conf file when installing X. I asked about this in a IRC channel I got a answer something like that X didn't need the xorg.conf anymore because it reconized most of the hardware anyway.
I wonder if this is something unique for debian or is wellknown fact and used by the whole linux community? Or did I get it all wrong?

Xorg will probe the system to autoconfigure itself, so if no xorg.conf exists or it's empty, You can run Xorg -configure to generate a xorg.conf.
Be sure to have information about your monitor and graphics card ready. About horizontal freq and vertical freq. As well as the chipset of your videocard, and the amount of graphic memory.

i'd advice doing this if you're missing certain screen modes, or when you feel it's not optimal.