I'll (mostly) stay out of the oil debate, but recommend the Motorcraft or Wix filters on these engines. And the Ford recommended interval was upped to 7,500 miles for this engine in '08 (dino or syth). So for gosh sake, if you're paying the premium for synth, you might as well get at least 7,500 miles out of it.
I'm running Costco dino + Motorcraft filters every 5-7 k miles, on a routine basis. I like the idea of running synthetic (esp. Pennzoil, but whatever is on sale) through one interval every year or two to perhaps gain the benefit of some extra cleaning over other oils. I've seen posts on Bob's the Oil Guy suggesting that Pennzoil has more detergents than Mobil 1.
In my Volvo with a Turbo, which is a more difficult oil change, I use Mobil 1 Extended Performance and run it 10-12k miles, with a long-life filter (usually Wix XP). The Mobil 1 Extended Performance is rated to 15k miles, but I don't like that oil for the 4.0L because I think the timing chain guides are more prone to wear in the Cologne 4.0L SOHC. Oils lose their ability to maintain the correct viscosity over time/miles. Cold startup--after oil has drained over night and before the oil heats and thins--is toughest service point for the 4.0L timing cassette