I, too, am late to the thread, but I have a great bike commute!
My bike commute is 3 miles each way, 2/3 through quiet suburban neighborhoods and 1/3 on a bike lane on a busy frontage road. It takes me about 25 minutes on the way there and 20 minutes on the way back.
It's mostly flat with some gentle hills both ways (maybe 30 ft elevation gain).
I ride a heavy (55 lb?) steel-framed step-through Workcycle Omafiets (
http://www.workcycles.com/home-products/handmade-city-bicycles/workcycles-omafiets-dutch-granny-bike) with blue chintz Basil bags on the back rack. Each bag can carry a full brown grocery bag full of groceries.
I've got a very upright riding position and only 3 gears. If I was going to buy the bike again, I'd buy the 8-speed, since the 3-speed gearing doesn't quite match my natural cycling preferences. For once being tall and needing a big bike had its advantages; the dealer was having a hard time moving this bike (not a lot of demand for 61cm step-throughs, apparently) and I got a screaming deal on it. It'll last me my entire bicycling life.
The reason I love this bike so much, despite the weight and gearing? I don't have to change clothes to bike in it. If I'm in a dress and heels, I can bike to work. If I'm in jeans and a sweater, I can bike to work. If I want to wear a suit -- I can bike to work. If I'm in a sarong and flip-flops, I can bike to the beach. (4 miles away on an awesome bike path) ;)
It has a completely encased chain guard, massive fenders, a built-in headlight, great brakes and a super-sturdy rack that can carry a large kid if necessary -- and an upright riding position that puts no strain on my wrists -- it's awesome.
It rides like a Cadillac, but is clearly built for comfort, not for speed.