When I was a cook in the Army, we had lots of knives in the kitchen but only a handful of types. Gizmodo recently released this article about what knives you must have in your kitchen. In short, the five knives are:

1. Cleaver — for when you cut up meats.
2. Chef’s Knife — the knife great for prepping veggies as well as almost anything else.
3. Serrated Knife — good for bread. The article says that a serrated knife is good for tomatoes as well but I prefer a recently sharpened chef’s knife.
4. Filet Knife — also called a boning knife. It is basically a smaller Chef’s knife.
5. Paring Knife — this knife is mostly used for dressing garnish when I was in the Army.

I agree and, if you do not cook much, you can get by with only a Chef’s knife.