I wrote a long article about precisely this, but since then I've changed my mind about some things. Here's the basics, in a nutshell --- ask lots of questions and you'll find out what you need to know eventually. (Incidentally, when Boar_de_laze shows up and gives advice, listen to him, as he's the best we've got on this subject.)
First of all, you need what I call an "anchor knife." This knife will do 90% of the work in your kitchen. There are 5 contenders, but I am almost certain that the one you want is a chef's knife.
A chef's knife is the single best all-rounder in existence. They come in French and German profiles, and are made all over the world. The best in most respects are made in Japan, but they can be pricey. Every other possible anchor knife gains and loses something with respect to this, so you have to ask yourself whether the gains are worth the losses. Your knife should be 8" to 10".
A santoku is a modern Japanese housewife's knife. Pro: it is shorter, ideally about 7", and takes a little less counter space. This is not an issue if you have a standard-depth American counter, but it may be an issue if you are genuinely terrified of a larger knife. Con: it is in every respect a little or a lot worse than the chef's knife.
A nakiri is an old-fashioned Japanese housewife's knife. Pro: it is shorter, on which see the santoku. It is a little quicker when rough-chopping vegetables. Con: it is truly rotten on all forms of meat and fish.
A Chinese cleaver is the standard Chinese kitchen knife. Pro: it is brilliant for chopping, dicing, and otherwise making things into bite-sized pieces with speed and accuracy. Con: it is not very good for other kinds of cutting, like slicing and such.
An usuba is the Japanese professional's vegetable knife. Pro: it is a terrifying, beautiful knife, capable of doing truly awe-inspiring things to vegetables. Con: it is mediocre at best on anything but vegetables, and it is about the most difficult knife in the world to learn how to use. It is also very expensive and takes a lot of maintenance time.
Conclusion: don't buy a santoku unless you are truly terrified of knives or have a teeny-tiny space to cut in (let's say 18" square). Don't buy a nakiri unless all the santoku things apply and you're a vegetarian. Don't buy a Chinese cleaver unless you are preparing 90% of your meals in bite-sized pieces (a la Chinese cuisine as it is usually practiced). Don't buy an usuba unless you have deep pockets, excellent hand-eye coordination, and are looking for an expensive and frustrating (but absorbing) hobby. Otherwise, buy an 8" to 10" chef's knife.
Second, you need to supplement your chef's knife.
You need a small knife for detail work, preferably a paring or petty knife. A paring is cheaper and at your stage of the game the differences are, in my opinion, trivial.
You need a serrated bread knife, for crusty bread. I am not convinced this is an absolute gotta, but everyone else is, so I acquiesce with good grace because I'm a nice person.
You need a long slicer, for things like ham. If you don't cut hams and sides of smoked salmon into thin slices, don't bother, but eventually you'll want one. They're fun.
If you ever do any butchering, you'll need appropriate knives. This includes a fish knife. If you don't break down fish from whole, skip fish knives, but everyone will try to push you to own one. You do not need any other kind of butchering knife unless you butcher things from primal cuts or close --- like big bone-in hunks of stuff, basically.
You will soon want what I call a brutality knife. This is just a honking big ugly thing that can break bones and shear lobsters and stuff. Just go to some yard sales and look around. What you're looking for is a really big, heavy chef's knife. Don't spend much on it, because you'll use it once in a blue moon.
Conclusion: what you really need is a chef's knife and a paring/petty knife, and with some dexterity and confidence you can get away without the little knife. Fortunately, however, paring knives and bread knives are cheap, so just pick one of each up and spend the rest on your chef's knife.
Third, you need to decide on your sharpening method. Have you ever sharpened a knife? Would you like to learn? In the long run, it will save you money and be an enjoyable skill worth having, but lots of people don't want to have anything to do with this.
Fourth, you need to decide on your budget.
Once you can tell us which knives you want to buy (the shapes I mean), your rough guesses about sharpening, and your budget, we can point you to some terrific knives that will make you a lot happier than anything you can find at Bed, Bath, and Beyond --- and stay in your budget.
Hope to hear from you soon!