There was already a discussion about that in the alpha2 iso thread but I think it's better to discuss this in a thread of its own.
Most people "voted" for smplayer in the other thread, which would be fine with me. It's qt based (nothing against gtk, but using a gtk based application as default in kde is just weird. try to do it the other way arround and you'll be lynched by gnome fans), its backend mplayer is a powerfull player. But: I'm having a strange thing about it on my Mageia box: I start it, I open an ogg file, I play it. I close smplayer, start it again and it won't play the same ogg file anymore. I close smplayer again rm ~/.config/smplayer start it again, it plays my file and so on. Anybody else having the same thing? Is it a bug or just pebcak? Others preffered dragon player, which is KDE's default. We could but I don't really like it, since it's a bit too simplistic in my eyes. I personally prefer kaffeine. It's working just fine for me, has many more options then dragon player. But some of you told it's not stable enough (in what way?) and some don't like it because it's not using phonon but libxine directly. The next option would be totem which I hate (just a personal thing). And it's a gtk application which I consider weird as default in KDE. Then there is kmplayer, I haven't really used it till now, but it's working and it's offering you playback of local files, optical media and tv (which I couldn't test due to not existing hardware. Next option would be xine-ui which definitely is looking a bit old fashioned. Did I forget anything? And what do you think? Oliver