I have admitted to being a fan of the Doc Savage stories in the past. Fun, targeted at teenaged boys, and quick reading, they are the classic adventure stories. I read all 181 original stories, as well as all the modern additions.
I have been searching for a similar series of stories, and am currently tasting the Matt Drake series by David Leadbeater. Not really in the Doc Savage mold, but more of an Indiana Jones on steroids, searching for relics, and fighting with organized mobsters (governments or whatever) to save them from evil plans.
Good action, somewhat believable plots (as long as the idea of Norse gods being real and 500M years old isn’t too far fetched).
Not sure I will stick with the whole series, but it has started well.