Mpeg1 & 2 codecs are native. Install the xvid codec
http://www.koepi.info/ which will also deal with most divx as well.
I'm afraid you are on your own with uncompressed avi.
Presumedly from a cam? Many cam formats are proprietary so the manufacturers site for instructions are your first stop.
Mov is usually not worth bothering with, but SUPER converts most everything to anything else.
It's freeware so give it a try. Your results will depend on the quality of your source. Mov can be pretty dire.
Usually with video conversion there is a free app out there that performs better than the commercial stuff. It's just a matter of finding it and getting used to using it.
AGK makes a first class job of making xvid avi from mpeg.
Video is a vast subject. You will just have to get your hands dirty and when you hit the brick wall, and you will, then it's research. Most apps have a forum where you can find answers.
Good luck.