He had one of the funniest bit scenes in Con Air, but he's probably best known for saving the world from disaster time and again as General George Hammond, on Stargate: SG1. Actor Don S. Davis passed away yesterday from a heart attack.
A full article, including a message from his wife to fans, can be found at GateWorld.
I'm a casual fan of SG1, but Don's supporting role was as integral to the show as the lead cast. Hammond was a father figure and a born leader, and Don gave him that strength. The character left the show several seasons ago, and they lost something when he did. Hammond couldn't be replaced, even by someone as experienced as Beau Bridges.
The SF community has lost someone special.