Updates to Team Fortress 2, Counter-Strike: Source, Day of Defeat: Source and Half-Life 2: Deathmatch have been released. The updates will be applied automatically when your Steam client is restarted. The major changes include:

Source Engine Changes (CS:S, DoD:S, TF2, HL2:DM)
Fixed more crashes related to Alt-Tab in fullscreen mode on Windows
Removed ConVars "r_portalscloseall" and "r_flashlight_version2" to fix a wallhack exploit

Counter-Strike: Source
Fixed a server crash caused by players committing suicide