Yea thats right, Cream Pie, thats what made and still is making HL so popular :)
Shuzer, its still only CS, NS and DoD cant keep the ship running, if CS never had come, Hl wouldent have been as big as it is, I think. Almost any HL player that now plays DoD, NS or any other mod has played Cs...
As already stated, Hammer is and will be more like radiant, because the mapping core is almost the same. Still I think Quark is the best editor for HL mapping, n' I think it will be for HL2 to, after a while. Of course this depends on what you are used to and feels comfortable with.