Most comfortable Boot

Any of the Redwing mock toe boots are extremely comfortable and provide a lot of ankle support. Have Goodyear welts so they can be resoled, and last quite a long time.
I recently got a pair of these, and after trying them out the other day, I have to say that I am in love with them. They won't even really require any break-in.

They are very lightweight, extremely comfortable, grip really well, and are waterproof. They are as comfortable, and almost as lightweight as running shoes on my feet, yet they give good ankle support.

Yes, they are fairly pricey. But as with most anything, you get what you pay for.