There are knives specifically engineered for every kitchen cut -- slicers, hackers, fileters -- but the most important one is your chef's knife by a country mile. If you don't have a solid chef's knife, you can grabfor just $39 plus free shipping on Amazon. That's $20 off the list price and a solid deal on a quality hunk of sharp German steel.
The key here is that this knife is forged, not stamped, which means the blade was crafted from one single bar of steel that was then heated and pounded into shape. There are some decent stamped knives out there but, in general, forged knives are more substantial, stronger and better balanced. They're also usually significantly more expensive, which is why this Premio forged chef's knife from one of the world's best-known producers for $39 is a nice value.
I haven't gotten my hands on this exact knife but I have used plenty of Henckels' blades and they're the real deal. In fact, I just bought a similar Henckels chef's knife for my brother (and paid about double).