You're not going to get a true performance tire that is also an all-season tire. Keep in mind that snow traction ability is ultimately going to limit your dry traction and to a lesser degree your wet traction.

That said, the Dunlop SP5000 will keep you safe in the snow while still giving you above average performance in non-winter conditions.

The Toyo FZ4 is also not bad when compared to the SP5000, it gets a bit of a bad rep because people generally don't realize it's an all season tire. Compared to real performance tires it's not very good but when looked at as an all season tire it's pretty decent. Its snow traction is not as good as the Dunlop.

So for you I'd recommend the SP5000 in 205/50-15.