You've received some good advice. Try all of the hybrids and flat bar road bikes you can, in your price range. My close friend bought a flat bar road bike, after being fairly sedentary and she is hooked. In less than a year she has clipless pedals and full cycling attire. I know you say you can't see yourself on a traditional road bike, but Giant does make road bikes with drop bars and a much more upright geometry.
I used to live in Tempe and can't see riding in that heat at this time of year! Be careful and make sure you hydrate all day long, not just when riding. I would go out at 5 AM, if it was me. I used to walk at that time.