The bars in the center are either strip clubs or purely male workers´ hang-outs the girls you see are at work.
The pedestrian Paseo Arturo Prat has a couple of pavement cafes, that are good for people watching.
A few decent spots along Av. O´Higgins a.k.a. Av. Brasil, and also the seafront parallel to it.
The otherwise standard hellish food court of the Mall Plaza has a neat outside area with a couple of bars and restaurants.