I've recently been rather successful leading with Focus Sash Tyranitar because it gives you the option to strike back with either Crunch/Superpower/Ice Beam/Flamethrower, and chances are with Sand in tact, you're usually in the drivers' seat within the first two turns. Considering you're generally guaranteed to dish out an attack and set up Sand Stream twice (if you opt to switch out!), a Naive nature with max Speed really helps you take advantage of the game. I tend to carry Thundurus/Excadrill/Garchomp/Kingdra/Scizor with that particular Tyranitar spread. I've been eagar to test competitively viable items to see which items work best with which Pokemon. I continue to adjust each set through means of how I wish to abuse my Life Orb, for example, to its fullest without wishing I dedicated it to a different member of my team. I always seem to regret selecting one item for another every five battles or so because the GBU metagame has all kinds of threats out there, and it is really difficult to say your team is prepared for the entire world.