I disagree, personally. Adriana Lima hasn't influenced the fashion industry, she isn't a muse of anyone etc. I just don't see how you could say she's is the face of our decade. Some people don't even know who she is or have seen her. I can't see her as important and special enough as a model to possibly be considered that.
I wouldn't say she's as big as Twiggy was, but in the present, she's definitely a huge model. I don't think the fashion industry is as big a cultural force as it used to be either, so it hardly matters to me that Chanel etc. isn't picking her up...fashion used to make headlines (Dior's New Look, for example) and be more than just borrowed ideas and corporate entities. I think for who we, or at least the USA, are right now, she's pretty representative of it.
But then again, Kate Moss is still Kate Moss, so I guess I would have to disagree with my original post anyway. Adriana Lima is the only model who even comes close though, except instead of being a fashion icon, she's a symbol of our decade's multi-ethnic standard of beauty and sex-fixation. (Also, one of my friends doesn't even know what Kate Moss looks like, but she definitely knows Adriana Lima--although she cares even less about VS than she does about fashion. It's not that extreme everywhere, but I would say Lima's pretty famous.)