I commute 4 days a week from North Seattle (Maple Leaf) into Downtown.  I generally leave my work clothes in my office so I don’t need to carry much on the bike, and after a few years of this routine, I’ve been able to whittle down my normal load.  That said, I often try to bring in donuts for the crew.  I also occasionally enjoy a nice fresh growler of pub stew (Fremont Brewing Co. is the current favorite).  Since I like to keep this stuff off my back, I have really found baskets to be a godsend.  If you can get past the dorkiness, they are really versatile.

I do prefer the basket on the front of the bike.  I had a dual basket setup on my mountain bike commuter for a while, but I found that mounts/dismounts were sometimes causing painful dings when I swung my leg around and caught the corner of the basket.  I also didn’t like the load hindered by the seat/light/toolbag.  This stuff got in the vertical plane, and just made the basket less effective.