Get some panda corydora.Great bottom feeders and they are cute.Looks like bottom feeders are going to be the tough ones to win my wife's heart.
Not sure if you made your final decision on the substrate,but if you want natural gravel,go to a home improvement store and get a bag or 2 of pea gravel.It's the same thing as the stuff in any pet store,and cost about $5 for 25 pounds.You just need to rinse it A LOT before putting it in your tank.
BTW,I'm not sure if anyone else will admit it,but I had a blue gravel 30 gallon for a couple years and loved it.I recently changed it to black gravel and am thinking of switching back. I bet most of us have had blue gravel at one time