C-B-S sportscaster Greg Gumbel delivered a speech on motivation last night at the University of Northern Iowa. The Loras College graduate has just finished an assignment at the N-C-A-A final four in Atlanta. He says it was a great tournament capped off by a championship game in which neither team played well.More and more college basketball players are leaving early for a chance at playing in the N-B-A. Gumbel says he not does presume to know what is best for any one player but feels option should be chosen carefully.Gumbel says the fondest memory of his 30-year career has been broadcasting the Super Bowl.