Hm. Tough question. To be honest I can't bring anyone to mind, partly because I had such a strong image of him from the books that it's hard to just pick a real person to match up. Not to mention you have to have the voice, too. I like this guy:
(Colin Firth), but I'm not sure he could have played a tough guy like Aragorn. (He was a WONDERFUL Mr. Darcy, though, for fans of Pride and Prejudice).
Honestly, I don't really keep track of actors, so I'm not good at picking 'em.