That would be difficult to tell,

(click to show/hide)

things like the giant gravity spell and the bloodline curse will throw off any attempt at providing an exact number

.

Just the ones we've specifically seen or have been told about.  There's bound to be an asterisk at some point with all the action in the series so I was curious if anyone had a rough guesstimate.

I know it's been over a month, but I figured I'd take a stab at this.  I only have a few.

Christopher Lee would have to be the Merlin, props to those who said that.
Michael Wincott would make a good Thomas, but it'd be strange not to see him as a bad guy.
Eric Roberts (from The Dark Knight) is my number one for Marcone, Liam Neeson would be a number two, although he's probably too tall for the role being six four.