Whenever I visit friend’s kitchens, I am often shocked at the bad knives I find there. The rest of the kitchen can be high-tech, but the knives are woefully inadequate.
Your primary tool is a cook’s knife. It should be very sharp.
A good cook’s knife is expensive, around 100€ and you’re starting to have good material quality. Unfortunately, it’s impossible to differentiate optically between good knives and bad ones. The market is saturated with really cheap chinese knives which don’t cut. (The cheap chinese cleavers you find in Asia shops are good too, but they scare me, frankly.)
Why a sharp knife? Well, for one thing, it is safer. Surprised? The issue with blunt knives is that one has to apply considerable force to cut anything tough, and thats the moment the knife slips. With a sharp knife, there is little effort involved. Less effort, less force, so if a mishap happens the damage is smaller. You end up continuously thinking about where the blade would go, though. Don’t put your hand behind what you are trying to cut, nor try cutting things without a cutting board.
To keep knives sharp the best option is to have them sharpened by a professional. If done well, you don’t need to do anything for at least six months.
You will have to learn knife skills, I recommend buying a book. The most important insight: your knife is is like a saw, so you need to make to-and-from movements, not simply press down.
Once you have mastered knife skills, there are a lot of activities which are suddenly a lot faster. Chopping onions, making thin slices of ginger – all easy.
It also means that a lot of the gadgets people use (such as onion slicers) will be useless and you can throw them away.
In terms of choice, I would go for a single cook’s knife. The best place to buy a knife is in a local shop, because you really need to feel them in your hands. There are basically two sorts of good knives, the german ones and the japanese ones. The german ones (WMF, Dreizack, or any of the other Solingen houses) are excellent and will put you back about 150€, the Japanese ones (I know Kai) are much harder, much sharper, but will set you back at least 300€.
If you want to buy a second one, buy a good paring knife (about 80€)