Lisa Kudrow is the most talented comedienne I have ever heard of. On Friends she can clearly show her talents because of the brilliant writing which enables her to show off her comedic skills.
She manages to bring comedy into situations you never thought would be funny and comes up with lines which are unimaginable and you could not see them coming.
Phoebe's songs are brilliant too. Although Lisa is not the greatest singer in the world she sings the songs herself and brings a sense of realism to them rather than have someone dub her voice.
A truly talented original.