That is a broad question to answer.. but I'll try my best to answer.
I'll be assuming that you are the sole commuter in the car, and that by "best" you mean in terms of miles per gallon and safety.
Therefore, in this case, the better the car means to have a higher mpg and a safer driving. Of course, higher mpg means lower gas prices, and safer driving means more reliability.
If you go to specific car brand websites you can figure out the basic information about their cars. Judging from your own sense of design, size, budget, you need to do your own research. Here's the a CNN article about ten cars that are known to be safe and fuel-efficient at the same time.