I am very much borderline, at 42 min for a lousy 7miles (I am really, really slow - partly by design in the morning, because I want to reduce the sweat factor - on the way back it's more like 30-34 min).

I'm riding on an old BSO, since I just started a few weeks ago, I figured this should do for now. My commute is actually not too far from what Barrettscv describes. On Devon (the crazy eastern part), North on Lincoln for a few blocks then through residential streets of Lincolnwood & Skokie for the remaining 5 miles.
Travel with a backpack on my spring rack (still looking for panniers), with fresh shirt etc. Keep shoes and pants, towel, alcohol spray and deodorant at work