Go read the bob is the oil guy forums. Thats where you'll probably get the best advice on oil.
Pennzoil plantinum is pretty popular right now. From what I've gathered its current formulation is fantastic.
Mobil 1 seems to be on the out, at least their most popular blends ie. 5w30, etc don't seem to be as "good" anymore. But I suppose its all relative to application, etc. Mobil1 isn't a "bad" oil, but I think there are better alternatives, especially for the exact same price.
Their 5w30 is pretty crappy if you just look at its base specs though, imo. There are a lot better choices in the 5w30 range. None of the Mobil1 5w30, 5w20, 0w30 or 0w20 ranges meet anything higher than ACEA A1/B1, which is just the generic oil rating. Pennzoil Platinum 5w30 meets ACEA A5/B5, which is the extended drain certification, so at least in that respect the Platinum has something in it that the Mobil1 doesn't that allows it to pass that test.
The two oils that interest me most are the German Castrol 0w30 and the Mobil1 0w40, they both have excellent specs and certifications and aren't really any more expensive than the regular synthetics. I'm not sure if I'm brave enough to try a 40weight oil yet though.
I'm interested in oils that meet the ACEA B4 spec actually. Its the diesel direct injection specification. Currently there isn't a gasoline direct injection specification, but I'm sure there will be one soon. An oil that is designed to work with a diesel direct injection engine is better than one not imo.
