Ron's obviously getting more skilled, so I'd say his wand picked him... not his mother
Anyone noticed we don't know what the essence of Hermione's wand is? We know the length and such, but never has the core been mentioned (if I remember correctly, that is... which I think I do)
"I'm for it so we can put Nuclear power plants up there, and then beam the power back to earth on a laser beam." ~ Whidden
I don't think Hermione's wand is important. Neville's is. He will for the first time get to buy a wand that will choose him. We are going to see a powerful Neville emerge. Draco, he can't be at his best if he has a wand his mummy bought for him.
It's a little odd that the ingrediants of her wand haven't been mentioned as yet, isn't it? I'm saying it is going to be important, and the reason it hasn't been revealed is that it will reveal too much about a connection between Hermione and someone else. Too much for us to know yet. Otherwise it would have been mentioned, I'm sure of it.
"I'm for it so we can put Nuclear power plants up there, and then beam the power back to earth on a laser beam." ~ Whidden