I don't mind too much how my boyfriend dresses as long as he's not wearing girls clothes (I used to go out with a bisexual guy who would wear women's leggings and being a straight girl, it was a bit off putting for me). My current boyfriend usually just wears a baggy T-shirt and joggers with a black & blue Londsdale jacket and trainers to match. I'm cool with that.
I'd be fine with him dressing like the dude in the picture to although I don't think that's quite the style he'd go for.
If I could decide what he wore, he'd be wearing a t-shirt, either his Lonsdale jacket or a denim or leather one, jeans and have his hair spiked up.
I'm cool with how he is now anyway (or I obviously wouldn't be going out with him), but what I described is a just a style I've always kind of liked.
Dunno why, but I always find if they're wearing a metal watch or something attractive/cute too. I have weird taste I guess.
As for shirts, waistcoats, ties and jackets all the time or stripey shirts, that's a bit too much like my brothers style for me to find attractive.