I'm happy with either of them.
I'd probably rather have Hall, because I think he'd help our offense more right away.  However, Seguin is a center, and generally, if you have the choice between a great center and a great wing, you take the center.
So, like I said, we really can't lose here.  I think the Bruins would take Hall #1, but I have a feeling that Edmonton might like Seguin better (again, due to him playing center.)