I've owned a pair of simple ballet flats from Aldo for a while. There happens to be a store in my neighborhood, and I found them while bored and browsing one day.  I wear them a lot - they're simple and comfortable.  They don't hold up on the days when I walk 2 miles or more (a lot of them!) but work just fine for when I use the subway or stay nearby. 
Since I heard VegWeb and Alicia Silverstone's Kind Life blog mention them, I realized they do carry a larger than average number of vegan shoes, like these.  A great option for those who like buying shoes in-person and don't live near Moo Shoes or similar!
Another tip - if your workplace is casual enough for boots, I have found that a lot of mid-end boots are vegan.  Maybe the larger size makes leather too costly?  Oddly enough, a lot of discount chains use leather - perhaps they think they need the perception of quality?  Worth looking into if you haven't taken a peek in the boots aisle in your basic Nine West or DSW lately.