ok i found the best one
MPEG StreamClip

the interface is a bit weired, but not that bad.

To work vid xvid you have to ad the xvid quicktime component to the library. And to work with wmv you have to have Flip4Mac pro.

MP4 files works extremely well. MPEG StreamClip is the best editor for MPEG files I've ever used.

There are other nice video editors for mac, but when it comes to none destructive/direct stream editing MPEG StreamClip handles it the best.