There are many factors that affect what will be an ideal purchase for you. I don't have the time now to walk you through that process, but hopefully others will or you can search the hundreds of similar threads from the last few years. Just to get you started though, here's an excellent general-purpose <$200 option that tends to satisfy the requirements of most people who don't have specific requirements that they know to identify:
I'm going to go somewhat quick and drop some terminology without defining it, but this should get you started.
All knives get dull, and an expensive dull knife is just as useless as an inexpensive dull knife (or even more useless since cheap knives tend to have thicker blades that can slightly compensate for dullness with their weight). If you want a knife that performs well, you will need a method of keeping it sharp. Ideally that means getting a set of waterstones and learning to use them, but it might mean getting a rod-guided device like the Wicked Edge or Edge Pro, or it might mean getting a Chef's Choice electric sharpener. They all have pros and cons, mainly dealing with learning curve, flexibility, and cost. You almost certainly don't want to get them sharpened by a "professional". First, because most "professional" sharpeners aren't professional in any sense but cost and will often end up just running your knife through a metal-eating pull-through device that leaves a highly unpolished edge. Second, because even if the sharpener actually does really know what they're doing, the cost (both in money and time away from the knife) will be high enough that you're not going to do it whenever your knife starts to lose its edge. It depends completely on use, but for a home cook, you'll probably end up wanting to do some degree of sharpening every few weeks to every couple months at the minimum. And if you're using soft European steel (e.g. Victorinox, Wusthof, or Zwilling Henckels), your edge will actually roll to one side and need some form of touching up every day, and multiple times a day at that. If you don't intend to invest in a good sharpening solution soon, then you should split this $200 budget into a less expensive knife and a basic sharpening kit. We can talk more about that if you're more interested in that approach. Chef's knife suggestions at the ~$200 price point are different from suggestions at the ~$150 price point, which themselves are very different from those less than $100.
I mentioned factors that affect what knife you should get. These include things like stainless vs carbon steel (roughly a tradeoff between maintenance and edge properties at a given price point), western-style "yo" handles vs Japanese-style "wa" handles, desired length, how heavy duty, your sense of aesthetic, etc. Regarding heavy duty, there will reach a point for any chef's knife when you'll want to switch to something more heavy duty so that you don't damage the edge. Even with a super soft, tough blade like a Wusthof, you won't want to try cutting through thick bones. Most Japanese knives err on the side of harder and stronger rather than softer and tougher, as well as being lighter and thinner instead of using weight to augment toughness. This roughly translates to taking a sharper edge and holding it longer, but being more easily damaged by improper technique when going through hard objects. That Mac I mentioned above is pretty stiff as far as Japanese knives go, but you still might have trouble going through a winter squash or frozen food without twisting the knife and damaging its edge. With an even thinner and less stiff Japanese knife, the risk of using damaging technique is greater. There are some Japanese knives, though, that do err on the side of toughness.
Some of the things that more money often but not always buys you are better grind, better alloy of steel and quality of its heat treatment (both of which result in better edge properties such as how sharp an edge it can take, how easily it takes it, how long it holds it, etc.), better profile, better handle, better appearance, better fit & finish (F&F), and better out of the box (OOTB) sharpening. Knives with a high failure rate during manufacturing, such as the super thin class of knives known as "lasers", also cost more due to the higher production costs. Stainless knives tend to cost more than carbon knives with comparable edge properties, and at a given price point, carbon knives tend to have better edge properties than stainless knives.
Not all of these things are worth the money to every buyer, and what's worth the money to a knife geek might not be to you, but hopefully these are some useful starting points for research!
Edited by Gladius - 6/25/15 at 5:47pm