Here's a pitch for my favorite commuter, a late 80's/ early 90's mountian bike with no suspension. They are pretty comfortable with commute-freidnly gearing. Throw a pair of slicks on them & you're good to go. My first commuter was a Rockhopper & I loved it. And they are pretty cheap, you shoul dbe able to find one on CL for $100 or so (dpening on where you live & the condition).