I adore
Martin (this spelling only unless you're specifically honoring a Dutch heritage- otherwise it just unneccesarily complicates things).
Denver and
Indy both seem a bit silly to me because I only associate them with the city in Colorado and the state of
Indiana.
Indy just sounds like a nickname anyway, not a full name in its own right.
Martin LeanderMartin EmmanuelMartin GarethMartin Tobias or
Martin TobiahMartin AngusMartin LeopoldMartin Jasper