In an odd way, my boyfriend.
When I met him we were 17 and he was so cool. He drank his coffee black, got straight As and knew everything, and was dating a goth fashionplate at the time. Neither of us had very well-developed styles, but I found myself imitating his all-black clothing. (To be fair, a lot of us were doing that, so I was fitting into a whole crowd, not just imitating him.)
I got way more interested in fashion than he did, but he's always appreciated the avant-garde, the unconventional, the gender-bending girlpower of androgyny, the idea of clothes as a statement more than a way of fitting in. So, I often think of him when I find things that look particularly cool to me.
(Today is our 16th anniversary [dating not marriage] so I might be feeling a little sappy!)
In terms of actual inspiration, Tilda Swinton is my icon. I don't copy her style per se (for that, I'd point to Kate Lanphear) but I just want to be her.