if i may play fashion police for a moment:
Dan-- snappy in silver... and pink! but he looks a little pale. is he under the weather? (get it? get it?

)
Rupert and Tom-- Reservoir Dogs in Hogwarts. aye there's your sequel franchise right there!
Emma-- almost had a Marilyn moment. the cut of the dress is very nice and flattering, but fabric is meh, reminds me of curtains.
Evanna-- from what i can see of the dress, looks great on her, wish she selected a different nail color though, to go along better with her dress.
Bonnie-- va va va voom! flattering dress, perfect shoes, great hair and make-up. guess what hon, you upstaged Emma. congratulations!
Phelps twins-- the press junket did them good. look at them handle it all like a pro. twin studs rawr!
Matt-- would've looked great except that he's sopping wet.
Freddie Stroma (Cormac McLaggen)-- if you can act, you're the next hot thing. i guarantee it.
Jessie Cave-- uh, is there a stylist in Wonderland? because Bonnie and Evanna got lost too once upon a time but look at them now. aint too late to climb out of the rabbit hole hon.
Helena Bonham Carter-- now we know who got Jessie lost in Wonderland.
Helen McCrory-- the bod that launched a thousand ships. oh yeah, and her dress looks nice too
Jason Isaacs-- *Beauxbaton sigh*
JK Rowling-- nice...... purse

oh and her shoes looks painful.
the elderly, venerable gents (Gambon, Rickman, Hurt etc)-- kudos to all for sporting some pretty snappy threads. except Robbie Coltrane. c'mon man, big can be beautiful, you just need to find the right cut (or wrap, in your case).
special shout out for the Trio who decided to pose in the rain along with all the drenched fans

. lets see the Transformers cast do that!