I'd say I agree with about 80% of the straight edge philosophy, and here's why.
I've never drank, or done drugs.
My family history is so messed up on both of those things. I have an alcoholic dad, who himself had an alcoholic dad, who himself had an alcoholic dad, etc etc.
Half my mom's side of the family is in jail for drug charges. One of my mom's brothers is permafried, I dunno what he did himself in on, but talking to him now is like talking to a child, and he's in his 40's.
I made a decision when I was pretty young that I was going to be the end of this cycle.
That being said, I don't really identify with the the people who call themselves straight edge.
I heard stories of guys ganging up on someone because they thought they smelled cigarette smoke, fist fights erupting, etc.
I had a legit reason to abstain, but I didn't feel like I needed to be some self righteous asshole who shoved my views in everyone's face, or worse yet, resorted to violence if I crossed paths with someone who disagreed with me. This is what the people of the scene pretty much expected from me, it felt like they were trying to start some lame little drug free street gang... so I walked away.
Plus, some of the really fanatical ones will tell you that being straight edge means you need to give up sex as well. I think they say that mostly because with their attitudes, they weren't getting any anyway :P
So yeah, I never wore the X, I like booty, and I like sodas with caffeine, so sue me!