I've never been to SF but those hills look nasty, I'd probably keep the road bike. What bike are you looking at exactly? The gearing for that certain bike should have little bearing on whether or not you get it, because it's so easy to change gearing. However, 82 gear inches seems a little steep, especially for a place like SF that has so many hills. For riding fixed, the best thing you can do in order to get faster, is working on spinning fast. If you can spin at a high rpm then you don't have to use such a big gear ratio in order to go fast, also it'll make going down hills easier.

Also, if you keep the gear inches the same, then it won't effect skidding other than the amount of skid patches produced. Most people prefer a bigger chainring paired with a bigger cog, because the teeth wear down a little slower.

I wouldn't suggest getting a track bike (a bike meant to be raced in a velodrome), because they tend to have really steep geometry that doesn't translate well to street riding, there are plenty of fixed gears out there that offer reasonable geometry/tubing that is suitable for street riding, just do your reading.