That would depend on what you want? An approximation of the stock unit? Something more sporty?
I like the Yamaha stuff best. They have both stock and the lowered more sporting bars with something like a 1-2 inch drop as well as a steeper angle drop.
Check the Yamaha site
www.yamaha-motor.com.
You can also go all out with some custom mounts and dirt bike bars ala euro street fighters