I'm also from Dayton area and typically fly on Delta.
I find that I usually get better Delta prices out of Columbus; in addition Southwest and America West fly nonstops out of Columbus.
Cincinnati is always more expensive though you can get a nonstop on Delta there.
I was able to get $185 for October 31 out of Dayton. I suggest waiting for a better fare. Wait until about four months out and then grab the next good fare you see. Of course if a great deal comes along at any time you should grab it.
One nice thing about Delta is you can check online how full the plane is by looking at the seating chart. If the flight you want starts to fill up, it may be time to buy. If only a few seats have been sold, there's no reason to panic.
If you want the best fare, check fares at least weekly, or sign up for a "fare watcher" email at someplace like travelocity.