Penfold said:
I personally find the concepts behind Sir Terry's villains more scary than the individual villains themselves.
Agree with you. Other than Vorbis, and maybe Wolfgang in several parts. I can't really think of a villain who is consistently 'scary' throughout an entire a DW book. Even the Cunning Man is more of an 'effect' than anything else, since he only physically shows up at the end of the book and has no lines.
Powerful villains, funny villains, annoying villains, boring villains, complex villains yes, but "scary' is hard to find. Maybe that's to Pterry's credit that for the most part, he refuses to give in to the old school version of the totally menacing, diabolically laughing villain and instead created adversaries who were the way they were because of their upbringing or culture, rather than simply a desire for power.