My number one pick for a great inexpensive gift to give a cook is a Japenese mandolin, aka a Benriner (the brandname). This is a tool virtually all cooks own, used for all manner of slicing, julienning and brunoising. Gnarly sweet potatoes become gorgeous chips. Under 20 bucks—can't beat it.
My most used small appliance is the hand blender, or immersion blender, a fabulous tool for pureeing soups and sauces, making vinaigrettes and mayos. Wouldn't want to be without one. (The above link is to an inexpensive CuisinArt blender, here's the KitchenAid version nearly 3 times as expensive but some feel it's worth it.)
If you're really in to cooking, these round cutters come in handy for all kinds of baking, cooking, plating needs.
I recently bought this fat separator and love it—simple ideas work best.
As Michael Symon said to me while we were working on his book, the microplane was a game changer for his cooking, allowing him to finish dishes with a hit of citrus zest at the last minute. Works with cheeses too, some whole spices, adding fresh garlic at the last minute.
The scale is one of my most important kitchen tools. I use it several times a week. This scale is small, efficient and economical. This little one, for measuring spices and other light ingredients comes in handy too. Though if you are a culinary instructor, your students will call it your drug dealer scale.
The Silpat, the Silicone Baking Mat is a great all purpose surface for baking. Love them.
I remember a story of an instructor who at at the home of the former president of the Culinary Institute of America, Ferdiand Metz, in Germany. The story stuck with me because the senior Mr. Metz personally steeled each guest's steak knife before passing it down and serving the meat. That's serious. For the serious steak eaters, Wusthof steak knives (OK, not inexpensive but wanted to throw them in).
And for the wine drinkers out there, a lovely decantor is a great gift. Yes, you also need a strainer funnel (if you don't, then you probably don't need to decant, yes?). I also like the wine areator—I swear I can taste the difference, but maybe I just like the sound.
Now, will I take my own advice and get my own shopping done NOW?! Or will I wait till the last minute and stress myself out?