@blackzombie #11
Did you ever look at the match games between Fischer and Taimanov ? There are at least (iirc) 2 games in that match where Fischer wins in brilliant style with bishop vs. knight. Very instructive games.
Then there are games by Fischer where he gets a strong knight on d5 in Sicilian defense games, but here against Unzicker he wins with the "bad bishop" :
http://www.chessgames.com/perl/chessgame?gid=1008416Here another fantastic game by Fischer, vs. Tal, where Fischer uses the strong bishop :
http://www.chessgames.com/perl/chessgame?gid=1008413As some other people already said, bishop in open positions have a long range. And a knight needs a lot of moves to go from one wing to another wing.
If the position is closed or semi-closed, and if the knight can go to a strong square, where it is firmly supported by a pawn or pieces (Think about the "octopus" knight on d3 in the Garry gambit Sicilian from the Karpov-Kasparov, where the amazing strong knight on d3 is supported by a bishop on f5), and if the bishop is not doing well, rather locked in by pawns, and no way to easily make the bishop alive again, then a knight would be preferred.
But this all depends on the position on the board and future prospects.
Fischer - Taimanov Candidates Quarterfinal Match
http://www.chessgames.com/perl/chess.pl?tid=79224