For those serious about cooking, walking into a cooking store is like a kid walking into a candy store - you want everything. Unless you have a huge budget as well as ample storage, it's impractical to buy everything you think you need, because the truth is, most of the things you'll buy will end up shoved in a cabinet or drawer never to see the light of day.
So what should you buy? Well each chef is different, but these items are things I think are invaluable in the kitchen to cut prep time, produce better results or just make your life easier.
Slow cooker
A slow cooker is a must have appliance for the busy cook. Simply put your ingredients in, set it and forget it. A few hours later, you'll have a fabulous meal with no major mess to clean up.
Bench scraper
A bench scraper is a rectangular piece of metal that usually has a plastic handle attached. Used a lot in bakeries to cut dough, it can be a great tool for a home kitchen. Use it to scoop chopped veggies off a cutting board into a pan, or even to scrape flour or other loose foodstuff off your counter.
Microplane
This is one of my favorite tools to grate citrus zest, chocolate, hard cheese, even garlic. I probably use it every day for something; I have two, one for sweet, one for savory.
Plastic squeeze bottles
You know the kind that you see on tables with ketchup and mustard? You can buy clear ones and put things like oil, vinegar, chocolate sauce, caramel, basically anything you want to drizzle instead of pour. Buy several because once you start using them, you'll find something you wish you had an extra one for.
Stand Mixer
This is an invaluable appliance, especially if you do a lot of baking. Use it to mix cake batter, cookie dough and whip cream in no time. But where it really shines is bread making. You can also buy attachments that will allow you to grind meat, make pasta or churn ice cream. It's definitely a worthwhile investment if you are serious about cooking.
Mandolin
This is a tool that slices vegetables quickly and uniformly. I have two; one that has a stand that sits on the counter and a smaller handheld one. I use both regularly.
Coffee grinder
Even if you don't use it for coffee beans, it's great for grinding whole spices, turning granulated sugar into powdered or even grinding small amounts of grains into flour.
Oven thermometer
Unless your oven is brand spankin' new, the temperature is probably off. Don't fret, that's just the way things are. Different spots can be different temperatures so be sure to move it around. Knowing your oven will give you much better results when baking or roasting.
Mortar and Pestle
Great for grinding spices, or crushing herbs or garlic, a mortar and pestle is an inexpensive investment that's easy to clean, easy to store and because it's used by hand, good for the environment.
Food Processor
If you want to cut down on the time it takes to chop, grate, or grind, a food processor will make your life much easier. It does more than just chop though; you can puree sauces, make pie dough, or slice vegetables in seconds. Perfect for those that want to avoid these mundane tasks and get straight to cooking.
These are all basic instruments of cooking that, for the most part, won't break the bank, but will make any dedicated cooks life easier in the kitchen.