I have two Ghost perk classes. One is my sniper class, which for the obvious reason has Ghost. The other I call my "Anti-Air" class, and it currently uses the Galil with Reflex site (with a teal heart as the reticle) and the Strela-3. I use that when someone gets the hind, attack chopper, or copper gunner killstreaks. The Ghost helps somewhat with those, but not always.
*Edit*
Also, seeing ppl talking about Second Chance, I have Second Chance Pro, and it still rarely helps me. I think the ppl that complain the most about it are the ones that dont make sure before moving on that the other guy is down. Once I see a 100 pop up on screen, I did my job, and move on.