For me, it's the Sigma Sting. Hands down, it's the best symmetrical ball I've thrown in a very long time. The Sigma Core and Fusion Pearl cover matches up extremely well with many of the patterns out there and is an extremely versatile ball for my game. If you can still get one, it's worth it.
I had a Hy-Road for a while and it is a great ball. The only reason I don't have mine anymore is because for my game, the Sting was just a bit better. But, there is a reason that ball has been on the market for more than 6 years now. It truly is versatile and still one of the best core/cover matches that will work for virtually any game.