Originally Posted by madhouse
. . . My recommendation is to buy a bike that you want to ride. . . .
This is the best advice so far. If you are not comfortable during your commute, you'll stop.
That said, I disagree with MichaelW. Surlys are not too heavy duty for a commute. I think they are just right. I especially like the flexibility to use skinny or fat tires and the dual pivot breaks. The Surly Cross Check and LHT are work horses, which is what I want in a commuter. I have not heard from one person who has regretted using a Surly as a commuter.