Airports for quick US entry.
A few years ago I flew LHR to Baltimore. I was off the aircraft and out of immigration and customs in about 25 minutes. I've just got back from Nashville and had a very similar experience on arrival - they have a small immigration facility but with only the BA flight and a couple of Mexican flights a week it clears quickly; only slight quibble is a longish walk from customs to the rest of the terminal to pick up car hire/taxi/hotel shuttle etc.
That said my record is prior to 911 at San Francisco in the "old" international building - 20 minutes flat plane to sidewalk.
What other US airports offer reliably (well, reasonably reliable) quick entry?