As long as you sign up by the short ordering deadline (see registration page) all marathon and half marathon registrants get a gender specific moisture-wicking shirt. 5K registrants get a 50/50 polyester/cotton shirt. Late registrants (if available) aren't guaranteed a shirt, but we often have extras after the race.
We also usually have a beer sponsor at the finish line and all participants age 21+ will get some free beer. We also have post-race refreshments like fruit, bagels, pretzels, cookies, etc.
Oh, yeah, you also get one of the most beautiful running courses around, fully stocked aid stations with smiling volunteers, on-course bathrooms, police and medical support, chip timing and live results/tracking, and an experience you'll cherish forever.