If you didn't previously own one, you probably wouldn't. I don't own a Porsche, if a law was passed banning them, I wouldn't miss them much because it would not effect me personally. However, if I owned a Porsche and the government wanted to confiscate it, I might be a little upset, especially if the guy next door who owns a Corvette is allowed to keep his vehicle.
Banning AR-15's will accomplish almost nothing, as a number of other semi-automatic rifles that use high capacity magazines are exempted from the proposed AWB and will continue to be readily available to anyone who wants to purchase one. The proposed AWB, like the last AWB, focuses on cosmetics, not functionality. Again, using a car analogy, it's like banning blue cars but allowing red cars, a meaningless distinction, especially since it really wouldn't ban blue cars, only the future production of blue cars. Is a Porsche with a whale tail somehow intrinsically different than a Porsche without one? Not by any measurable degree. The same is true regarding the weapons included in the proposed ban in comparison to the weapons which would still be fully available for purchase and ownership. I realize that frustrates a lot of people who would like to see all firearms magically vanish from private ownership but sometimes the truth hurts.