I would still use your moisturizer to keep your face in check. No need to change the balance, especially if you are not breaking out.
For oily skin I would recomment the Bare Escentuals line! Here are my recommendations for prep and wear:
1. Apply Bare Escentuals Prime Time Foundation Primer Oil Control, $21. It helps with cutting down the oil after you've applied your favorite lotion and helps the mineral powder stick (and not look like powder!) A little goes a long way.
2. For the foundation- I would recommend Bare Escentuals bareMinerals SPF 15 Matte Foundation, $28 even though that may be over kill you could totally get away with Bare Escentuals bareMinerals SPF 15 Foundation, $25.