You've opened various cans of worms with this comment, so I'll rattle through my choices:

Best Bond: Sean Connery

Best Sherlock Holmes: Jeremy Brett (with Basil Rathbone second)

Best Dracula: Christopher Lee

Best Mary Poppins: Julie Andrews (obviously, and with no offence intended to Emily Blunt, whom I love in other roles)

Best Superman: Christopher Reeve. That one isn't even a debate as far as I'm concerned, it's scientific fact.

Best Batman: Christian Bale

Best Doctor Who: Tom Baker (classic era), Matt Smith (modern era). In the case of the latter, I think David Tennant had stronger stories overall, but I prefer Matt Smith's Doctor by a whisker.