Should I take GIS or Hydrogeology..

I am an environmental geology major with a minor in bio… I have the option of taking Intro to GIS or a hydro-geology course… the truth is I dont know what I want to do when I graduate next summer… but I heard that GIS is a good class to take for job prospects but at the same time I also heard that hydro-geology is what most geology majors do right out of college. I think Im leaning more towards GIS but I need some persuasion and advice. Thanks guys!