Speaking of the most decisive factors to include a guitarist in the list, for me it was mostly players that I spend most time looking up to, imitating and trying to find inspiration in both their technique and music. That said, I did include a number of players just because I especially enjoy "the guitar factor" in their music, even if I never felt compelled to try this type of playing myself.
Breakdown by geography.
UK 11
Spain 2
France 2
Czech Republic 3
USA 5
Japan 1
Sweden 1