For my '95 Landcruiser that asks for 5W-30, I use Mobil 5000 or High Mileage 5W-30. It's a synthetic blend oil.
I change it every 6 months, I don't put on more than 3,000 miles in 6 months!
I used to use Pennzoil, but the engine had a funny (but characteristic) "clatter" at first start-up...