Look to your interests. What do you feel passion about? If the answer is: "nothing" then keep the arcade site
I'm fully going to agree with the last poster. If the blog is something that your going to want to continue to run for quite some time it HAS to be something your passionate about or really enjoy. No matter how open ended most subjects are if they don't fully hold your interest your writing topics will begin to dry up, your posts will become less frequent, and the blog will become stagnant.