I like the voice of Sven, Mikael, Delacourt, Llewlyn the Nightingale, etc. Most of those guys are a-holes, but they do have the best voice.
Karita's voice sounds bloody horrible. The wagon drivers sing better than her. Lisette etc. has the better female singing voice.
Luaffin baffles me. A dunmer bard singing praises to Ulfric Stormcloak in an Inn where the proprietress hates dark elves and one of the regular customers threatens dark elves and anyone who sympathizes with them in the streets.
Lurbuk has the most fun personality to me, though!