I’m going to contradict everyone above, because, frankly, they’re wrong. 
DON’T buy Henckels or Wüsthof.
In fact, don’t buy ANY stainless steel knives. If you’re serious about your knives, buy only carbon steel, and a decent sharpening stone.
The above-named knives, which again stay away from, have become popular as people have become lazy. They’re made out of such hard stainless steel that they hold their edge for a relatively long time. This is seen as a boon to people who are too lazy to actually take knife to stone. But they don’t keep their edges forever, and will eventually become more and more dull.
Unfortunately, since they’re made of such hard steel, you CANNOT SHARPEN THEM at home, and must take them into a professional knife shop to give them a new edge. (The steel rod these lazy people use will help you keep the edge longer, but doesn’t actually sharpen the edge; it only straightens it where it becomes bent and dented from use.)
If you want a really sharp knife, that is always just as sharp as you want to make it, you will use a carbon steel knife.
Carbon steel is softer than stainless steel, so it doesn’t keep its edge as long, but it’s–here’s the key–just soft enough for you to be able to sharpen it at home, on a standard whetstone.
So if you have a carbon steel knife, you can give a quick sharpen on your stone, and keep it RAZOR SHARP from use to use. With a stainless steel knife, it wil be razor sharp to beging with, but will gradually become duller and duller, and you won’t be able to do anything about it.
So. To recap:
Carbon steel, cons: strictly cosmetic; subject to darkening and rust, must be rinsed after each use or will rust–any easy enough habit to get into, believe me.
Carbon steel, pros: will always be just as razor sharp as you’d like, with a few passes over a stone.
Stainless steel, cons: cannot be sharpened at home, so will gradually become duller.
Stainless steel pros: shiny!
Unfortunately, due to the ascendance of Convenience and SHininess over utility and excellence, carbon steel knives are hard to find nowadays. The internet of course makes this less of a problem. However, they were easier to find in the past, so my best knives have all been found at flea markets and thrift stores. I have some knives that I bought for $1, because they had a few rust spots that I steel-wooled right off, that Sabatier would sell for $180 today.
You can also spend a great deal of money on a whet stone, if you buy it at a fancty knife shop. I bought mine at a hardware store, a stone intended for tools and axes and chisels, etc., for a few bucks. So I’ve spent less money than anyone I know on my knives, and I have the best knives.