there is no other major commodity that correlates close enough to our dollar. IMO, dollar depends on a trade balance (imports vs exports), rate expectations and overall strength of the economy.
USO is good trading vehicle short term as it invests in front month futures. MER is pretty high and constant roll drags performance. Companies such as XOM, BP, RDS, TOT are great oil proxies, just be aware of their debt load.
I am staying clear of oil right now. Biotech/healthcare and financials could be more interesting plays as money flowing out of tech need to find new home.
Dow to GDP ratio chart
After spending many years in Wall Street and after making and losing millions of dollars I want to tell you this: it never was my thinking that made the big money for me. It was always my sitting. Got that? My sitting tight!