Hi Gillian,
Just sent you two big emails answering some of your questions.
Seriously, go to CityBikes on SE Ankeny and check out either the Surly Long Haul Trucker or the Cross Check - both steel, tough as nails, able to add on fenders, racks, etc., can put on a huge variety of tire sizes. They have drop bars but do NOT cut the fork, so the handlebars are way up high (unless you want them to cut them down). I left mine the way they were and am happy for now. They specialize in commuter bikes and are an employee owned coop. No high pressure at all.
Good luck.
Regarding braking know this: the front brake is stronger than the back brake. Don't slam on the front brake alone or you will likely go flying - on any bike. Use the front and the back. The Bike Gallery has free clinics throughout Spring to late Autumn, usually from 6-7 (see the website: flat repairs, commuting 101, basic maintenance, and gear shifting that rotate over & over).
"Opportunity is missed by most people because it is dressed in overalls & looks like work" - Thomas Edison