+1 to what Adrian said on fit - Muy Importante!
Both those bikes will get you through your daily commute... But I would recommed the 'cross bike. THe major reason has to do with the fact that it can accomodate a wider, more rugged tire. That will make it possible to do a little "off-roading" with a lot more grace!
I lived in the Mojave Desert for 17 years and commuted to work by bike while living there for eight. I can kinda relate. My weapon of choice for off-road fun was a hardtail mountain bike, but a cyclocross rig would have done OK in most situations.
Hope this helps!