Ten is, and probably always will be, my favorite Doctor. His personality was way over-the-top, and though Eleven is a close second and Nine is definitely third, I thought the last few episodes of the most recent series touched perfectly on the fact that both of them were far too vengeful and violent. Ten was focused on saving. Save the world, save the invaders of the world, keep them both far apart from each other. Plus, how could you NOT love a Doctor who is the oldest being in the world, the last of his kind, and absolutely cannot stand to see a child crying - to the point where he will move heaven and hell themselves to fix whatever is the matter. Eleven also worried too much and frequently mucked with his own time stream. Ten was very strict about that, and I loved the way he interacted with his companions. You can definitely see how he brought his own personality to the role, as well, and I think he really enhanced the Doctor. Ten was a hard act to follow, and I'm wondering if anyone after him will ever match up.
I'm also wondering when Eleven's going to kick it and let Twelve enter the scene.