Bishop VS Knight

Best Answer:  It's ALL dependent upon the particular position. If the board is 'open' it is much better to have bishops as they can easily swing from one side of the board to the other. However, in a 'closed' position (where the pawns are locked in the center) the knights are more effective as they can hop over the blockades. When your center pawns are locked and you have that same colour bishop behind them, it's basically in 'jail'. Hence, the term 'bad bishop'. These are of course general principles in the middle game. 

In the endgame when it's King and minor vs. King and minor, it can depend on the pawn structure as well, but in a different way. For example if the pawns are on two sides of the board it is usually better to have a bishop that can swing back and forth quickly to stop them. However, if the pawns are all on one side of the board the knight can be more effective. It still cannot move around the board as quickly, but now the advantage of being able to 'change colours' is what tips the scales towards the knight.