Which league do you think is the best?

Based on what exactly

I guess for development.

Easily the KHL, you got Russian kids playing against adults as young as 17.

If you're trying to develop a player to play in the NHL, I would say its the AHL since those other two leagues play on bigger ice surfaces which means the style of play is different than that of the NHL. But if you are saying which of those leagues is better in terms of skill, I would likely say its the KHL, then the SHL.

KHL has better talent. Some of it's players are future/former NHLers.

I think the AHL is the best for development. It's the mini NHL and the best young players, who are a notch down from the total elite players and are drafted usually play there. They come over from the KHL or SHL a couple years after being drafted and learn the game in the AHL. There are countless examples, but Mikko Rantanen is a prime example of a guy who just recently did it and made the jump to the NHL from the AHL successfully.

what is the SHL?

Swedish hockey league

KHL Has A Lot Talent And Skilled Hockey Players Also They Have Former NHL Players Like Datsyuk Playing Over There

All these leagues have great talent but I think the AHL is the best because two reasons. 1. Scouts and NHL coaches can keep a good eye on you 2. You are playing against some players who will eventually play in the NHL and veterans that get sent down

1. KHL
2. SHL
3. AHL

The exception being defenseman breeding - go to SHL for that all day.