Nice question but it's not an easy answer.
There are many amazing coders it would be unfair to single out one.

Also IMO to calculate the best coder there are many attributes to consider.

Technical skills?
Multiple languages?
Tidy code?
Good documentation?
Commits to the community?
Good Bugtracking?
CSSU coders?

This isn't easily/fairly calculated from most downloaded package or most packages released.

It's definately not in community spirit to single out one but I am sure we could name a good few.