To "win" the "war" against an idea, you must destroy all motivation for the people to use it so that they simply will not use it. You can't "win" against terrorism, but you can "win" against it's users.
The simplest and least destructive solution? Give them what they want. Really. That's the only reason anyone ever resorts to drastic measures. That's never going to happen, and the terrorists will keep on terrorizing in defiance to the end.
The current strategy is to smack the crap out of anyone even related to terrorism, which really isn't such a great idea on multiple levels. It's not accurate enough. Like lobbing miniature nukes at ants. Too big of a response to too small of a target, far too much collateral damage, too expensive for the results, swings too much support aways from the efforts and we burn ourselves out like we have been doing since the Vietnam war. We can't be "World Police" anymore. People are sick to their stomachs of it. 9/11 was enough to rally congress to initially approve for this sort of thing, but really we'd need a 9/11 every six months to keep the public support going. The sheer amount of resources we've thrown out there to stop dirty fighting, we're imploding. This is exactly what a number of terrorists are out there to do, and I think they're winning at this war of attrition. We can't keep up this tactic.
I remember soviet Russia. They had this whole quelling thing down. Any troublemakers and their extended families disappeared, end of story. Terrorism to trump terrorism. As per what we're founded on we don't have the option of resorting to this, and technically fire to end fire is stupid.
We can't afford to keep at this the old fashioned way of throwing money at it, nor can we resort to some dirty tactics ourselves... really I think the only sane thing left to do is try to solve the problems that created the terrorism in the first place. But good God, can you imagine how much actual effort our politicians would have to put in to solve public relations? We need magic like we haven't seen since Nixon/Kissinger.
EDIT:
What did we do to provoke 9/11, pray tell?
If I recall:
It dates back to WWII. We're partly responsible for Israel's creation as a nation, which is what ticked everyone off in the MidEast. Then as they have their wars over there, involving Israel, and we kept giving some support to Israel. At several points, we stepped in with full blown military actions. The end result is a generation of people who believed G. W. Bush Sr. was personally in that bomber blowing up their home and that while Israel is still of the devil, America is it's Imp. The Twin Towers were originally involved in a previous terrorist bombing, an old fashioned bomb-bombing down in the basement or something, but they were caught and arrested. One of the ringleaders swore that even though they were stopped, the towers would still fall. I remember one of them swore that. Almost a decade later and someone finally got around to it. Someone else around here who actually took some history classes should do a better job of telling this.