I think the feeling is that including CS is fine, but a lot of folks (like me) would rather play DM and will probably never fire up CS. We'll play HL2 and go back to UT2k4 for multiplay.
I'm in that boat. HL2 is and always has been to me a single player game. I tried CS a long time ago (before source), never really got into it. I saw a friend playing CS:S and it didn't impress me much. Just a glorified deathmatch IMO- and I find deathmatch boring.
I have a feeling that HL2 will have high replay value, and am hoping that some mod developers make some good missions/maps for it. But if I want multiplayer action, I'm going straight to UT2k4 onslaught.
Jim