Keldorn, pretty much every time (invaluable NPC in my opinion), and Valygar quite often as well
The others I've tried at different times, but I can't say that I found any of them particularly appealing. If I want to play a bard, I'll play one myself. Mazzy isn't too great, and I prefer Jah as a druid to Cernd.
Each to their own
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"Only two things are infinite, the universe and human stupidity, and I'm not sure about the former." --Albert Einstein