Sylvester McCoy is the Seventh Doctor

Sylvester McCoy's Doctor is arguably the best incarnation. Not that you'd have thought it from his inaugral season though. It's apt that the Doctor was lumbered with Bonnie Langford as a companion for his twenty-fourth season, because it's basically a big, horrible, gaudy pantomime. The four stories contained therein are little better than Chris Baker's run.
Thankfully the series got a new script editor, Andrew Cartmel. He turned things around heroically between seasons, and the remainder of Sly's run was fantastic. No longer a goofy prat messing about with silly little adventures, the Seventh Doctor became a much darker, more manipulative figure, as Cartmel sought to return the character to his mysterious origins. "Chess-player on a thousand cosmic boards", this Doctor was not above manipulating his companions and always knew more than he revealed. No longer haphazardly landing at random places, he would plot his way to deal with 'unfinished business.'
So it was third time lucky for Nathan-Turner when it came to casting the Doctor. McCoy's previous work in showbusiness consisted mainly of juggling, playing the spoons and putting ferrets down his pants, so perhaps it was more luck than judgement.
When Chris Baker was fired from the role, he was reluctant to commit to coming back for a regeneration scene, even when tempted with a final story to write him out. The BBC solved this little problem by having Sylvester McCoy dress up in the Sixth Doctor's costume, lying on the floor, then regenerate as his body was turned over. Of course this means that he couldn't do anything except lie there, so it appears that the Sixth Doctor was killed by banging his head on the TARDIS console. Perhaps a fitting end to such a poor incarnation.
Although a major improvement on his predecessor's, the Seventh Doctor's costume still left a lot to be desired with a hideous pull-over emblazoned with multi-coloured questioned marks under a more sedate jacket. Far better, and more useful was the umbrella with a question-mark handle.
Unfortunately, just as the series was peaking, with its glorious twenty-sixth season, the BBC rather sneakily axed it. Unlike the 1985 'hiatus', when they announced the cancellation, provoking a 'Save Doctor Who' campaign from the Daily Star, this time they just stopped making it. They kept saying it would come back, but not until seven years later, in 1996 did Doctor Who return to our screens.
So McCoy flew out to Vancouver to record his regeneration scene, where the Seventh Doctor steps out of the TARDIS and is shot by some Triads. He'd be OK, but when he gets to hospital he is killed by primitive human medical procedures, and regenerates...

Sylvester McCoy
IS
The Seventh Doctor
(1987 - 1996 (technically))

Companions