We are not talking about HDTV 16:9 TVs here. Aspect ratios are important when printing out your digital photographs. Most wonder why your digital pictures looked cropped or have white borders when printed out. Why? Aspect ratio - of course.
A digital picture has an aspect ratio of 4:3 to mirror a computer screen, while traditional file prints have a 3:2 ratio to match 35mm film negatives. Therefore, something has to change in order for a digital picture to fit on traditional print sizes.
Two things you can do. (1) Have a white borders on the picture so you can see the entire picture. Or, (2) Crop the picture to fit the aspect ratio of traditional film but that means making some decisions on what to cut off.
There are some digital cameras that now offer a 3:2 aspect ratio.