Mobil 1 is trash. I hear the high mileage M1 is a lot better than the normal stuff but I wont ever use it again. Royal Purple is what was in my car when I spun a bearing, so again I would stay away from it; it breaks down very quickly, I've read too many oil analyses of 5w30 Royal Purple breaking down to 20wt sheer strength over time.

Redline is good but pricy and is not a full synthetic. Motul makes good oil too. Personally I'm running German Castrol 0w30 and my car seems a lot happier than with the Redline 10w40, especially on cold starts. I've got a couple friends running Shell Rotella T 5w40 with great success, its cheap, fully synthetic, and made for diesel motors so it lasts forever under strenuous conditions.

http://www.bobistheoilguy.com/ has good forums for researching other oils.
http://www.blackstone-labs.com/ offers oil analysis so you can see how well your oil is holding up, as well as what other contaminants have made it into your used oil.