brand means nothing. Its ford, chevy, porsche. They all have good and bad, top models and bottom ones. They all make sport utilities and sports cars.
What style is the question you should be asking. Thats depends on if you need to carry stuff, how much you need to carry and how you want to carry it.

2.5 miles is a short ride. Old mountain bike with slicks would be the cheap entry level to see if you like it. Personally I would recommend a better name like Trek, Cannondale, Specialized, Jamis. If it has a "Ashtbula crank" and made in the last 20 years it is typically the sing of a low end HEAVY bike. Proably the most common bike you could look for used that would make a decent commuter would be something like a Trek 820. $80 usually will buy a good one.
Suspension on the road is typically just extra weight and rear suspension tends to waste effort better used for forward motion.

Take a look at this thread and you will see budget commuters made out of Rigid mountain bikes.
http://www.bikeforums.net/showthread...r-Bicycle-Pics