I went splurge on a new bike last week. It's a Litespeed Xicon. It's a lot lighter than my Salsa Casseroll. Partly because my new bike is titanium and partly because the new bike doesn't have a rack or fenders. I also think that it's a little more aerodynamic.
It won't be my everyday commuter bike but I have ridden to work a couple of times. Each time I took an extra set of clothes the day before. This is because I don't have a way to carry much. The first commute was almost 3 minutes faster than my previous best.