I'd say McNabb and *gulp* Benson. Here's why: The Raiders have lost to the chargers 11 straight times now and theyre not likely to buck that trend in week 1. They'll likely be playing from behind and rely heavily on the passing game. Throw in a solid SD run defence and the three-headed RBBC that McFadden will be in and its better not to start him in week 1 (at least until we get a better idea how many carries Bush and Fargas will steal from him). Benson, on the other hand, is not in a three headed committee. He is the primary back in Cincy. While he's averaging a dismal 3.8 ypc, the Bengals showed last year that theyre not afraid to give him 30 carries in a game. They'll be playing a questionable Broncos defense and have a good chance to be playing from ahead with all the chaos going on in Denver right now. This may be the only time you'll start him all year, but in week 1 I'd go Benson.
I echo Benson and McNabb. McNabb for now is almost a no-brainer. Cutler and Palmer have question marks heading into the season. Start off safe with him. Benson is the primary back in CIN and Denver has a soft defense. I think they're going to be pounding them relentlessly.