Pertwee and Davison were my favorites.
The actors' ages have been up and down over the years, but mostly down. Hartnell was 55 (but seemed to play him a lot older; I would have said he was in his 60s). Troughton was 46. Pertwee was 50 - nearly as old as Hartnell, but played a much more active character (the only incarnation of the Doctor who was more than willing to settle issues with his fists). Both Bakers (Four and Six) were 40 when they took the role, with Davison only 29 in between. The Doctor got older again, with the 44-year-old McCoy, and then younger, with the 36-year-old McGann. Then New Who started with Eccleston, the oldest Doctor of the three, who was 41, followed by 34-year-old Tenant and 27-year-old Smith.
Now Peter Capaldi is 55 years old, the same as Hartnell when he started, bringing it full circle.