Bo, at EXPVLSION OF THE BLATANT BEAST, has a long and complicated post on Taliesin. He discusses the relationship between the historical and the mythological figures; the difficulties in scholarly analysis and the vast problems with neo-pagan interpretations. Also, towards the end, there is a Dr Who reference ;).

I have nothing to add, except that back when I read an awful lot of fluffy Celto-fantasy, I always thought Taliesin was particularly hot…