Personally, I would Craigslist a used Japanese steel bike and install Gatorskins or Schwalbes. Those are bikes you cant really go to far wrong with, no matter what.
After a year, when your miles and skill level have risen, reeavaluate your needs. 99% percent of new commuters want to move on to something different after they've been riding for a while. It would be sad for you to spend a lot of money on something that you may be unhappy with later. Others will offer different views, but I say a used bike with good tires(flats are very undesirable on your way into work, trust me!!!!), good lights and mirror that can be transferred to a new bike later.

Best wishes, be safe !