Yes, meat is a good source of protein, mostly because it has branch chain amino acids that are not present in foods that contain protein, but variety is the spice of life.
The list is long for other non-meat protein sources: egg white, beans (kidney, garbanzo...), tofu (don't knock it till you try it), nuts, avocados, cheese, yogurt, milk, cottage cheese (great with pineapple), peanut butter (my personal favorite).
The difference, at least not the main one, is that some of the other protein sources will also have non-saturated and saturated fats. As long as you go easy on them and enjoy them in moderation you'll be fine.
mindgarden: best tuna salad ever is tuna, diced onions, diced tomatoes, diced pickles, coleslaw-style chopped lettuce, and lime juice. Mix it all together, chill for an hour, and damn good.
briarhawk: Meat is an excellent source of protein since it has a higher percentage of protein than other foods and has specific branch chain amino acids not found in any other foods. The drawback is that it takes more energy to digest, and for some people it can be heavy and cause some discomfort, making them feel extremely full. Flipside is that non-meat protein is easier on the digestive system, but doesn't have those particular amino acids.