General American. That NYTimes dialect quiz puts me in the Midwest typically (Rockford, IL was my closest city last time I took it), with a broad similarity to that across the Great Lakes region (Buffalo and west) through Iowa and the upper Midwest and somewhat into the Upper Plains. That's consistent with my family background, and other than a bit of time on the edges of the South as a child I didn't really live anywhere with a distinctive accent (other than American) growing up.