Hcoregamer00
The 'H' stands for hentai.
Pretty sure this is his theme: http://youtu.be/cBQA3u0td2w It's been in pretty much all the episodes at least. Flatline was the first episode I properly noticed it in, as in it just wasn't background music.
I haven't really noticed his theme, but it does feel like Capaldi's doctor.
In terms of Doctors: Capaldi > Smith > Ecclestone > Tennant
My list would switch Smith with Tennant.
So for me it would be Capaldi > Tennant > Eccleston > Smith
Sorry, I just didn't like Smith's doctor as much as the others, and I LOVE Capaldi's doctor.