First off, welcome to the Bay! There are plenty of great rides just outside your door.
Depending on how strong you are (and how well you ride hills), pay attention to the gearing on the bike. It is extremely difficult to find a ride without going up a bit. If you are buying new, pretty much every bike you will look at will have compact (50/34) chainrings. Larger cogs in the rear will take a bit of the sting out of climbing.