Tom Izzo, do not leave Michigan State for the NBA. You are one of the Top 10 college coaches ever, and loved by fans all over the US. Don't do it. The NBA is a different animal, you have to deal with bigger egos, the fact that they all make more money than you (thus think they don't need to listen), and knowing that it's not pure competition but business.
Remember that run you had to the Final Four this year? That wasn't about the money, it was about heart, effort, and defense. The NBA doesn't care about any of that.
In case that argument hasn't swayed you, I've created a list of recent great college coaches who went to the NBA, and their results.
A list of those who crashed as NBA coaches:
Rick Pitino
John Calipari
Tim Floyd
Mike Montgomery
A list of those who succeeded as NBA coaches:
N/A
Any questions?