What to do??

I've got $300 to buy a new bike to go with the kiddie-kaboose bike trailer my mother-in-law gave us for Patrick. I'm not sure what to get. I want to get a good bike that will last a long time and do well on any type of road surface. I'm thinking of getting one of these Schwinn Bikes but I'm not sure. The first two look to be the exact same except one is aluminum and the other is steel. The third has a spot for a basket to be added to the back if wanted. What do you think? Here's the link to the site. Bike one
Bike twoBike three