In the clip monitor and timeline monitor, I get choppy sound. I've tried both 0.4 and 0.5 svn, the latter of which produces choppy sound with ALSA and no sound with any of the other options.

I'm using an old cs46xx based sound card if that matters at all. Interestingly, I can capture the sound just fine. If I capture in KDEnlive and then play the captured file in Xine or Mplayer, it works perfectly.

I probably created a duplicated bug.

Can you check this

viewtopic.php?f=16&t=92

is the same problem?

Have you tested rendering?