H.264 is the best 'lossy' format around nowadays. Movie download issues (click on blue link)

In my tests using H.264, it far surpasses DivX, but that's a personal opinion (unless of course I provide file sizes examples, data rate & res details, snapshot examples, etc. of quality). Though I guess the limitations of DivX are obvious to those who have converted files to both DivXPro & H.264 before.

As Sleepless pointed out .. both AVI & Quicktime's .mov can be 'Containors' which may contain one of many video & audio formats within.