If I get bored of TF2 but want something else before I reboot, I may hop in for some CSS. But I run Linux now, so there'd have to be a damn good reason for me to boot windoze.
Played it when the HL2 beta was out, played it for a year from release and then went back to 1.6, I never did pay for it so no not anymore. Kind of wish I could though, wish my graphics card didnt crap out.