My problem with alignments is that they've always been way too abstract and cliquish. They actively stifle characterization in my view.
"Why'd you beat that guy up?"
A. "cuz im evil lolz"
or
B. "because he was pretty clearly evil, and I'm good!"
And yet, the act performed is the same. People don't care or think about their actual motivations, it's just a name. Which team you're on. Sure, the base meanings of good and evil are amalgamations of personal ethics and real-world comparisons; people inform their idea of "good" based on their own ideas of how good things should be, and generally evil is simply an antithesis to this, but in the end it just comes down to whether you want to rebel against the establishment in some way or "do the right thing", whatever that means.
I usually use the system from D20 modern. Players are required to disclose four or five things, in decreasing order of importance, that they find important and devote themselves to. If good or evil (or law or chaos) has a place on that scale, then that's fine, but it is in this case clearly a personally-defined philosophical concept, not an overwhelming force.
(Okay, going over this, I'm pretty sure my perspective is mostly based on the actions of the players I've had over the years, who have chiefly been of the hack-and-slash variety (for whatever reason). Maybe I'd have a different view if I'd looked in the drama clubs and such...)