Slide is not at all kind to groups with more than a 1:1 ratio of guys to girls. Vessel is also very picky and has a cover of $20. Not meant to dissuade, just to set reasonable expectations.

However, if those fail, that's not a bad area to be in. Cantina, Rye, Ambassador, and the Redwood Room can all be pretty good on a given night; I feel like it's just the luck of the draw. Bourbon and Branch, a bit deeper into the Tenderloin, has a pretty nice bar in back they call the "Library" which you access from the big door on the O'Farrell street side to avoid having to wander through the main part of the bar. There's no real sign; it's just a door. If they ask you for a password, usually it's just "books."

Bambuddha's also pretty great, I've found, on the weekends, especially if they open up the pool area.

There's also Cigar Bar (live music) and Bubble Lounge (dance floor downstairs) but I haven't been there in a while. Those are also close to the clubs in North Beach, like Dragon (if that's still even around). They're all on Broadway east of Columbus.

But Polk Street and the Marina are also great choices - it's just a more homogenous, fresh-out-of-college crowd, which may be what you're looking for. Hell, that's usually what I'm looking for...

Also, if you're looking in the Michael Mina range of restaurants, I'd suggest stopping in at Gary Danko and just eating at the bar if a reservation is hard to come by.