If the Trek 7.1 is truly like a new bike, I'd go that way in your position and had a limited budget. Won't have to worry about what might be worn out and need replacing, and don't think you'd find anything better that was new for that price unless you go to bikesdirect or some other online outlet.
10 miles a day is very minimal so I wouldn't be so concerned about the benefits of drop bars and if you're commuting in an urban area, there are advantages to being more upright.
Now if you think you may want to do longer rides or do something else, that's a different story.