I am answering the phone less and less with caller ID. If there is no caller, I don't answer. If there is an 800 number, I don't answer. If there is some organization, I generally don't answer.
depends on their professionalism and pushiness. I like taking surveys actually, they don't bother me at all...I'm rarely rude to a telemarketer, I try to keep in mind that they're just working in a crappy job and trying to earn a living. I don't want to make their job harder or day any worse.
I just hang up on them halfway through their schpiel. That way, they don't have to subject themselves to any more rejection. They will just patter on for 5 more minutes and when I don't answer them, they will think we got disconnected.
I use my cell phone's voice mail feature as a call screener. If they leave a message, and I want to talk to them, I'll call them back.