Question : Converting/editing avi,mpg,mov,rm (real play files) and mp4??

First off what is the best format to keep movie files in??
avi, mpg (mp4?) or mov??

Also I'm looking for an app that change convert the following.

avi, mpg (mp1, mp2, mp4) mov and rm

from one to the other or to at lest the best :)

Also an app that can edit them (cut and pate) bits.

I'll give 50 point to each question.

Answer : Converting/editing avi,mpg,mov,rm (real play files) and mp4??

Maybe worth mentioning here is that DivX is a proprietary format from Microsoft. The hacked version of it is called DivX ;-)

One good site to start at is
http://www.divx-digest.com/

As for an editing tool: Try VirtualDub, very professional and free.
http://www.dvd-digest.net/downloads/files/encode/virtualdub14.zip