Generally speaking, vehicles with automatics are easier to find and hold their value better. Decide ahead of time which type of transmission you want. 4X4's are very popular now, even with people who don't need to drive in snow or mud. Keep in mind that you will pay extra for four-wheel drive, and there will usually be a reduction in gas mileage. If you pile on the miles, you better think about a car with good gas mileage.
Thirsty cars can be expensive to drive, especially since gas prices seem to always be creeping up.
If you're stuck in traffic a lot, an automatic saves you working a clutch and stick shift. For example, if you have a bad back, lumbar support may be a non-negotiable item for you. Or perhaps you are short and need to raise the driver's seat. If there are features you know you simply must have, make a list of them as a reminder. Once you've decided on a class of car, look at individual models.