Originally Posted by
Cream Soda
Never get a bike from Walmart, ever.
They're not built to last. They all break down. All of them. It's not a matter of if, but a matter of when (depending on how much you ride it).
For commutting a hybrid (mountain/road) will be your comfort/efficiency; a standard road bike would be purely efficiency (If you aren't trying to lollygag around, this will get you from point A to point B the fastest, at the expense of comfort. They don't have things like shock absorbers, which add to comfort, but also absorb your power, so you go slower)