If we win this fight, what comes next?

It really doesn't pay to speculate about losing. I'll be looking for a new homeland. (I'm too old for front line service in a rebellion.)
But if we win, what, then?
I would suggest the first thing to do is clean house.
Considering the nature of our enemy, you can count on any space they vacate to be infested with more bugs than Joe's Apartment. There are a few of those guys past whom I would not put booby traps. Every stick of furniture and every object should be replaced.
I'd put in new drywall to remove the last traces of Santorum from the air.
The same goes for staffers. If they worked for Republicans, they're spies now. The money is just too good to resist.
The rest depends on the scale of the victory.
If we can flip both house and Senate, we can start bombarding the chimp with legislation. Cheney will tell him to veto it of course. But the illegal overseas adventures can be eventually starved for cash.
Most of the time the Monkey house versus the congress will result in ugly gridlock. Which is better than what we have now.
If we flip only the House, the best we can do is obstruct the chimperor. As stated above, gridlock is better than what we have.
It can be the function of the flipped house to chew the chimp's ass until the rest of the Republicans can be purged from congress.
I can't rationally suggest more than this. Sweet as impeachment would be, we need to get down to business of repairng the damage they've done.

What a mess the media will rip them a new one!!!!!

REALLY NASTY ... for us ...

Let the Dems seek the will of their constituents on specific questions. Do the people we represent want the US to simply withdraw our troops from Iraq? If so just do it. Back out of GATT and NAFTA? Whatever the people want.
Give the voters the sense that they are being listened to and that their desires are being implemented and they can only blame themselves if the consequenses are less than what they bargained for. That is how representative government is supposed to work isn't it?

Just make an effort to get a clear idea of what the constituency wants, not just the rich ones who can camp out in the office for days on end and pony up large amounts of cash for the election.