I didn’t see this before. Consider George’s Deli on the south side of Market St. between 6th and 7th. I actually recommend the Polish Sausage more than the hot dogs, though. And since I always eat there during the week when I’m working, I can’t swear he’s open on weekends.
There’s also a new hot dog place that last I passed was about to open just around the corner on 7th St (across from the new Federal Building going up)–it looked like it would have possibilities.
San Francisco is also loaded with push-cart hot dog vendors. They are too pricey for my regular patronage ($3-4 for a hot dog) but when I have tried them the dogs were pretty good.
For a greasy spoon special (hot dog, burger, whatever you want), I love Red’s Java House on the Embarcadero next to SBC Park. If the weather’s decent, get your food and eat it outside by the Bay.
Truth is, I eat as many dogs at CostCo as anywhere–they are cheap and good. It’s on 10th St. between Harrison and Bryant if you’re a member.