Pokemon you REALLY want to use, but shouldn't?

[Nez]

Kind of the opposite of the "Pokemon that you couldn't be bothered to use" thread, I'm wondering if there are any pokemon people wish were viable but just aren't. I don't mean NU or UU games, I mean wanting to be able to beat a salamence with a Delibird, that sort of thing.

Mine:
Mawile, Delibird

 

[Falkon]

Marowak especially, but a mono-water team next. Yeah, I know that's a team, but...still.

 

[Surgo]

This has been done to death.