I blame my preference switch from Nick to Lacroix on the role playing game I participated in over a couple of years. I wrote Lacroix and I suppose occupying myself at close range with his ways of thinking increased my fascination.

Otherwise, in my case, it often depends on the actor. If I enjoy seeing an actor, or watch a series because of that actor, I usually like the character best, that is portrayed by that particular actor.

Let's see what other fandoms I can come up with in which I like one character in particular (not sure if I can get 10 at all):

10 fandoms in which I have a singular favorite character:
- Forever Knight: Lacroix
- Star Trek (TOS): Kirk
- Star Wars: Luke Skywalker
- Murdoch Mysteries: Chief Constable Giles
- LEXX: Prince
- Black Harbour: Nick Haskell
- Forever: Henry
- Arrow: Malcom Merlyn
- Vampire Diaries: Damon
- The Originals: Elija

10 fandoms in which I have no singular favorite character:
- Rookie Blue
- Highlander
- Castle
- Sherlock
- Star Trek - Voyager
- Star Trek - TNG
- Star Trek - DS9
I'm sure I missed something or someone.