12 galaxies is still open.
The pier 7 replica is called pier 3.5 and is in San Mateo. Other good parks in the bay include the Berkeley Park, sunnyvale, and Santa Rosa. Those are my favorites at least. Oh, and crocker amazon is another park in the city, though most people hate that place for a variety of reasons (small, poured unevenly, only one or two people can go at once. little hood kids playing in the park and getting all in the way.
Pop's and thee parkside are the bigger "skater bars" but if you want to meet women they are not necessarily the place to go. Great spots to see some alcoholic pro skaters though, if that is your thing.
Downtown kind of sucks now, the best luck you might have with spots is to go to random hilly residential areas, and look for driveway spots. In places like the sunset anywhere you go will at least give you a long line of grass gaps and driveway banks. And you'll probably find some crazy shit that is like no other spot you've skated. Its a treasure hunt, and its fun as hell. Just pretend to be Tommy Guerrero in your head.
As far as famous old spots, the sf public library is back and hopping, just make sure you get there after 7.
MIssion is going to be the best bet for cheaper foods and just cheaper shit in general. If you want cheap and delicious I have three words: tacos, tacos, and tacos. El farolito is decent, as somebody said, and just about any taco truck will do the trick. Other good ones are el toro on 17th and valencia, el tonayense on 24th and treat (I think), and Casa Sanchez on 24th and york. A tip for casa sanchez, its right by the potrero skatepark, and if you bring a board with you and bring it up, they'll give you a free drink with your food, and all the free chips and salsa you could ask for is free to anybody. You can spend like three bucks and get 2 tacos, a drink, and chips and salsa. Not too shabby. I also like Tommy's joint on van ness north of the civic center, cheap carved meat sandwich type place. Some pretty good sandwiches to be had for pretty cheap.