Shoulder mounted rocket launchers would definitely be effective. But really, there are any number of ways for a terrorist to stir up trouble that don't involve high tech stuff...
Take a small private plane out over the National Forests and drop several hundred highway flares.
Shoot the oil filled transformers at electrical substations with high powered rifle bullets.
And of course, the shopping mall attack, the elementary school attack or the hospital attack.
That kind of thing. Low budget. Big huge impact.
Honestly, we should be grateful that the enemy is so frickin' stupid that they don't do the simple stuff.