Committee heads or not, you still need votes to get bills passed. The anti gun forces (be the Dem or Repub) aren't going to have enough votes to make a majority in the Senate, let alone break a filibuster. Of the seats that the RNC is going to lose in the Senate that I can see happening (Ford has a shot at beating Corker, Webb will probably win, and Casey is all but certain to knock off Santorum's desperation tactics campaign), they're largely pro gunners as well. Even if Brown knocks of DeWine, they're both anti gunners so no loss there.
The House is a tougher nut to crack because there are too many races up in the air to really be able to see what'll happen.
But putting all that aside, I think A) the Dems will have some institutional memory and not want to push another AWB and B) they're going to spend the next few years going after the GOP and Bush over Iraq-gate, Foley-gate, Plame-gate, Halliburton-gate, FISA-gate, etc.
Gun control is just really far down their agenda. Sarah Brady held a press conference early in September here in gun controller friendly Maryland...and the only people who showed up were me and the NRA reporter.
In short...I think it'll be bad, but I think the hyperbole about how bad it'll be is way, way, WAY exaggerated here.