The only other player [besides Joe Alexander] from the first-round class of 2008 to have their third year option declined was the Celtics' J.R. Giddens.
For clarification, this means that J.R.'s contract won't be renewed for next season. He'll be an unrestricted free agent, and can still sign with the Celtics. He'll still be on the roster until the end of the year, barring some sort of trade.