Tried to play an mp3 this morning. Amarok message: "xine was unable to initialize any audio drivers" Mplayer: "jack cannot open server". Had a slight déjà vu and kicked myself for not having logged what worked in my case, which was deleting the card in Yast->Hardware->Sound and having in autoconfigured again afterwards.
No risk involved, provided you did not configure the card by hand and don't care about losing the old config.
N.B.: This happened on Xanthippe, Tisiphone and Archimedes consecutively. Is it just me???