To sum up, there is no question that SFO is a much better terminal, with far easier ground connection to SF (via BART, shuttle or car). The food options at SFO are vastly better. Having said that, I often use OAK for these reasons:

1) Routes -- I haven't checked lately, but Southwest from OAK has had the only nonstop service from SF/Oakland to San Diego. Also, Aloha from OAK operates some of the few Bay Area nonstops to OGG and KOA.

2) Airport location -- if your origin or destination is in the East Bay, OAK is more convenient, especially if you need to be on the road at congested times. Such congestion is, sadly, not limited to rush hours.

3) Fares -- certainly not always, but quite often OAK will have much lower fares to a given destination, and more cheap seats available. (Not surprising, given the presence of Southwest and Jet Blue.)

4) Reliability -- heavy fog and rain can wreak havoc at SFO. They must land the planes one at a time, and this can quickly cascade into long delays for lots of flights. Long flights to/from SFO get priority, but flights from the western USA can be delayed for hours in these situations. Since OAK has only one runway, it is usually not affected by such conditions (although delays at other airports can indirectly cause delays at OAK).

As for the "Clampett factor", to those who really have a problem mixing among the unwashed masses, I suggest that you get over yourself. Just about everyone has some air travel experience now, so you can't really say that there are real inconveniences being around working folks. You are no better than the family from Livermore that has saved up for a couple of years for a trip to Disneyland.