I dont think its a Player specific problem. Its a problem with KDE or X. Please try to tell me if you encountered similar problems.
Another thing, while kaffeine is ON, mplayer cannot play a video. Is it like only one video plays at a time? Windows can have more than one mplayer playing different videos at the same time. Cant linux?
Fedora Core 2 is fine I guess. Core 3 is available, but when I upgraded, my K3b, kaffeine, wifi, and many others were broken. So I downgraded. Will surely get FC4.
And I am thinking about kubuntu 5.04. I heard its fast and light.