Does anyone have any practical tips on how to diffuse tantrums or on how to get my 2 and a half year old daughter to STOP whining?

I love her more than anything, but the whining is driving me crazy. There are times when I literally have to leave the room, because I feel like if I don't, I'll snap. I try to be as patient and understanding as possible but she has a way of pushing my buttons like no one else.

I try to be very concious of how I respond to her tantrums because I don't want her to witness any reciprocated aggression (that's not going to teach her to stop). But I'll admit a few times she has brought me to a breaking point where I have really yelled at her (I know I'm "human" but I still felt guilty for DAYS afterward).

I would really like to hear from other moms who have kids this age, and what you do to handle (and stay sane!) during a "whining session" or full-blown, kicking & screaming tantrum.

Thanks