Okay so I figured out that the whole double-shooting, weird delay/lag with the mouse was the result of some combination of having these settings enabled:
- pointer acceleration on in SetPoint
- enhance pointer precision in Windows mouse settings (OS form of acceleration)
- smooth mouse movement in CS:S
Disabling all of these things and setting -noforcemaccel on the CS:S launch options has fixed the mouse issues and eliminated any mouse acceleration. Unfortunately, I must have been playing with at least some acceleration before because no matter how I tweak sensitivities I can't get the movement back to what it was like before so I've had to just deal with some really crappy accuracy while I readjust. Will probably just take time. I notice in HLStats my accuracy is way down now but HS% is higher - odd.
Here's a VERY detailed mouse optimization guide if anyone is interested:
http://www.overclock.net/computer-peripherals/173255-cs-s-mouse-optimization-guide.htmlAs for vsync, I've kept it enabled since I do get some tearing if I disable it. It stays at constant 60 fps and I'm okay with it since it feels pretty smooth. And it never drops even if there's a lot going on in the screen (thanks to the 8800GTX).