The only reason I have call waiting is so that I don't miss a call...like from mom or something important while I'm talking. Like you, I usually don't put the people on hold, unless its a quick "give me an answer or time" call. I'll have the call waiting person leave a message or I'll call the person I'm on the phone with back.

I DO have caller ID and wont pick up the phone unless I know who it is. MUCH easier to avoid telemarketers that way.