Many drivers know the process for changing their own oil, and it always feels good to avoid a trip to the quick-lube shop down the street, as you can really save some cash by changing your own oil. However, before you get underway, make sure you have an understanding about the various types of oils that are available and which ones are right for your car.
For starters, always consult your owner's manual before beginning a repair like this. Every vehicle is different, and the manual is there for a reason - to guide drivers toward making smart decisions. Some vehicles may not "play nice" with every single type of oil on the market, so it's important you know your car's limitations.
That being said, oil type is very important. A poorly-suited oil can drag your performance down dramatically, while a good oil can actually improve performance beyond typical standards. It all depends on which oil you choose to use and how often you change it.
The most common oil in use today is multi-grade viscosity. When dealing with oil, the biggest enemy is temperature, and this is why multi-grades are preferred by many. The oil actually changes viscosity based on the temperature, so this oil is very adaptable and won't give you many problems. Most vehicles use 5W-30 oil, but you can play around with this somewhat. For example, 10W-30 and 10W-40 oils are great for older engines and cars that will be driven in hot weather.
Some enthusiasts insist that "straight-weight" oils are actually superior - and in some ways they are right. These oils are classified as 30W and 40W, but they don't change viscosity based on temperature. Still, since these oils are thicker, they do better in hot temperatures - you just have to make sure that you do an oil change before winter comes or you could ruin your engine. If you live out in Siberia, you can also go the opposite end of the spectrum - straight 10W oil is good for very cold weather.
Finally, there are synthetic oils. These really have no drawback - they provide superior performance in nearly all aspects. The one caveat is the price - they cost triple what normal oil does. However, for the ultimate "set it and forget it" type of oil, there's no beating it.