What color of hair would look good on me?

I like my hair how it is, but I feel like I want something different. My hair is dark blonde and gets lighter in the summer. It goes a little bit past my shoulders. I wanted to dye it auburn before and I really really like the color. My hair was darkish brown before and that looked nice too. I'm gonna swim a lot as soon as it gets nice out, so I need a color that will stay in and not get affected by the cholorine. I might just keep it the same but I want some suggestions. I have a round-oval face and bluish-gray eyes and a million freckles, but they don't stand out too bad because I have a little natural tan so they blend in more than a pale person's. Any help is appriciated.