if people are expecting Obama to win the "cable news chatter" battle, you're gonna be disappointed. I think that voter registration and turnout, state-to-state campaigning (I include targeted ads in this category), and debates will matter more. So I don't think there needs to be a huge emphasis on "attacking" in the Republican sense.
I know people like to say "bu bu, what about Kerry", but Kerry's campaign was nowhere near as energetic or organized as Obama's is right now. And even then, Kerry only lost by a few points nationally (and the election came down to one state). Also, as I've seen said before, most people just saw Kerry as "not Bush" so there wasn't really any motivation there. Obama is actually someone people seem to want to vote for, so that makes a big difference.