The real estate boom has been good to agents like Mr. Neeley. Last year, he helped sell 48 houses, worth an aggregate of $56.7 million. This sum was nearly seven times the value of what he sold five years ago and more than any other agent in northern Westchester County, according to an analysis of multiple-listing data. He said he earned close to $900,000."I always wanted my business to grow," said Mr. Neeley, 51, as he pulled away from an open house in his white Bentley Arnage this month.