Hair up or down in August?

I don't know what I want to do with my hair! I love the look of an updo generally -- neat, out of the way, less to worry about -- but I hate the way I look with my hair all up.

I'm considering doing 1/2 up or down with some parts pinned up, but I don't want to look like my everyday hair. I have pretty straight hair and dont know how well my hair would hold a curl in August for an extendd period of time..

Any thoughts?