If you feel that the standard weapons are getting kind of old, or you just want to ramp up your arsenal, you should check out the Counter-Strike Weapons plugin for Sven Co-op. It contains all the classic CS 1.6 firearms. The only caveat is that they have to be configured for map-specific instances, as far as I know, because weapon plugins in Angelscript only apply to the maps that the plugins are used in. Download it here.
Here is some footage posted by the plugin authored by KernCore: