If you're suffering from wacky amounts of head-bob, try this:
1. Hit the tilde (~) key to bring down the console
2. Type "cam_inert" and hit enter to see what the current value is (in case you want to put it back)
3. Enter "cam_inert 0", and hit the tilde key to close the console
The headbob was really bugging me after I patched, so I poked around in the console until I figured how to turn it down -- mine somehow got set to 0.7 after I patched (not sure what it was before, but it seemed more extreme).
It seems to save the value once you've done it, so no need to do it again every time you play.
Setting it to 0.0 also seemed to make the response to mouse movements snappier, oddly enough.
For trippy fun, try cam_inert 0.99