what Chipcom said...

Steve you may wanna do a search in the commuter threads, lots of great general advice there.

For commuting you need to consider your route, riding style , what you'll be carrying (do you need a rack?), but also whether you can bring your bike inside at work. My lock-up situation at my job has a huge effect on what bike I'd use. Generally speaking street lockup=theft or damage, so you want to limit the bling factor and your $ investment so you limit losses when* they happen.

*"when" , not 'if'