CS will be played, this gen, next gen and for many more gens to come. But so will UT and Quake. BF really needs some improvement to become popular again, COD is a proper franchise as well.
But personally... I"m looking forward most to Halo 3. Not that many pc shooters coming out i'm too interested in. For me Halo 3 is going to be *the* multiplayer experience this gen. Well it could always turn out to be shit... But after beta I'm quite sure this will be my #1 shooter. And then there'll be Gears of War 2 somewhere this gen as well..