I'm with Blueberry, go with a second bike.

I just today did the first ride to work on my new back-up commuter bike. It's an old Novara Randonee frame that I had built up with drop bars. I'm getting pretty serious about bike commuting and having a back-up commuter bike will be handy. Plus it's fun having a whole herd of bikes! I'm up to 6 now!

I also have a Ruby too, a 2007. I may ride it to work in the summer for fun occasionally, but it's mostly a road ride machine.

If you know your size well and can do some assembly work bikesdirect sells some good bikes that would be great commuters. People talk about them on other forums. The Windsor touring bike looks interesting and I think it's only around $600.