tackling rifter:
3x 250mm arty with emp
1x standard missile
mwd, web, 2 point scram
nano, cap power relay, rcu/nano/cpr/istab
Use the MWD to get within 7km, turn on web @ 10km, scram at 7.5km, orbit and pew pew while your buddies pound the crap out of him. Should be able to perma-run the mwd. If he's not packing smartbombs you can orbit closer.
edit: Just fly what you can afford to lose. If losing a caracal means you can't replace it, probably shouldn't fly it. That's the nice thing about tackling frigs, they're almost always useful, cost pennies, and insure for almost full cost. That and they're damn fun to fly. Some of the funnest times I had in eve were burning towards D2/BoB 200km sniper fleets, get there with shields gone and just get the tackle on one before they were able to warp off. :]