Finally found this thread. My pick:
Gallen Lo (Ambition)
I know a lot pf people choose CBWH but I prefer his role in Ambition (plus he's hot in there!)
Adam Cheng (Greed of Men)
I actually hate this character so much that I wish to jump into the TVB and shot him to death.
Deric Wan in (Looking Back in Anger)
I was too young to remember more but he was a classic villain.