Here's a great example of the tremendous difference depth of field can make when composing an image! Thanks to Buck Cooper for emailing these photos to me...from the Field of Heroes (the memorial set up at Century High School to honor our fallen soldiers). What a "humbling experience", as Buck wrote, "walking through 4440 crosses".
The first picture, here on the left, was taken with at f32 (a very small aperture)...and required over 1 full second to compose (absolutely must have a tripod for long exposures like that!). Everything is clearly sharp from foreground to background. The second picture, was shot at f2.8 at 1/100 second. Taking a photo with a wide open aperture like this results in much more light being let in, therefore, a very shallow depth of field...blurring everything but the focal point, which, in this case, is that front cross.
I want to stress, again, that neither of these choices is right or wrong...it is simply a personal, creative choice and should have a lot to do with your subject matter, the available light you have to work with, and the end result you are looking for.
In this case, with such a compelling subject matter, both depth of field choices are particularly valid. Nicely done Buck!