[Koller]

Gambling for a living by Sklansky&Malmuth p.62-63

In fact, the most successful gamblers are the big sports bettors.

There is an obvious reason for this. Sports betting is the only "game" where you can increase your bets in proportion to your bankroll and still have virtually the same edge. You can`t do this at the racetrack without dropping your odds. Increase your bet size in blackjack and expect more "heat" and a less profitable game. Move up to bigger stakes in poker and you run into other pros who will cut down your potential win rate dramatically. In case of slots, promotions, and tournaments the prizes usually stay fixed regardless of your ability to gamble higher. Such is not the case in sports (unless you are betting such huge amounts of money that you move the line; in Vegas this would take about $50,000 per game if you spread your bets around).

So if you really do learn to beat sports, do your homework, watch as many games as you can, keep records, and treat it like a business, you can forget about that measly $100,000 a year we promised you. In sports, the sky`s the limit.