My mom verbally abuses me; what should I do?

I'm almost 17 years old and for the past few years, my mom has been verbally abusing me. She calls me "stupid" pretty much on a daily basis and when she gets really irate, she tells me to "drop dead". She's depressed, so I'm sure she takes out all of her misery on me. She blames me for most of her problems and is always putting me down.

Just today she preached about how I only care about school, college, and my book I'm working on (as if I'm supposed to care about anything else at this age). She wants me to go to a crap college near where we live because she is going to have a hard time finding a place to live after I go to college and expects me to take care of her (even though she's perfectly capable of taking care of herself). Even my 30-year-old sister agrees with me and she knows what our mom does to me.

I'm just scared that this verbal abuse is going to turn physical one day -- every single day it's like she's mad at me and I'm at the point where I'm about to explode. What do you think I should do?