If you are trying to decide which one is better for cutting and trimming food, you should look into serrated or plain edge kitchen knives. Both have their pros and cons. Serrated knives are great for getting into those tough to crack eggs or tough to cut tomatoes. The problem with serrated edges is that they can be pretty difficult to maintain and clean.
A plain knife will cut through just about anything that you throw at it. You can also use a plain knife to easily slice veggies if you need to prepare your food quickly. I would suggest purchasing a multi-purpose knife like a Japanese chef knife if you plan on chopping anything really well. If you only intend to slice food, a plain knife will work just fine. If you are going to prepare foods, the serrated edge may be a good idea to help cut down on your preparation time.
When deciding between serrated edge kitchen knives and a plain knife, you will obviously want to consider how often you plan to use your knife. If you are just going to use the knife occasionally, a single-edged blade will be fine. If you are a serious cook, or if you make a lot of food, you will probably want a two-edged knife that offers some style and will last you a longer time. If you do buy a serrated edge knife, make sure that you clean it after every use. This will prevent dulling and increase the life of your knife.