I use Mobil 1 synthetic 5w30 around every 5000 miles, I use mostly Bosch or K&N oil filters, kia filters lately because I bought a box of 10 for my wife's optima, it had the possibility of metal shaving, even though it passed Kia's checkup, figured I'd use kia filters in case something did happen with the Optima's engine.
It's an automatic, I usually do a drain and refill every summer.