When I was 10, it was very easy to shop for gifts for me. Clothes and LEGO.
Clothes are always a good gift for a growing kid. They’re going to need them anyways, and you might even manage to appear “cool”, or at least not “lame” if you pick something that resonates with them.
LEGO was also great. Even if I already had the set it would still make a great gift. The influx of different amounts of different bricks would set me off coming up with new designs to build with these new parts that were not previously possible.
But as I’ve grown up, my tastes have grown more expensive, and more precise. Now, instead of wanting a computer, I want a MacBook configured in some specific way. Instead of wanting a helmet, I want a medium Shoei RF-1000 (mainly because it’s the only one I could find that fit). As I’ve aged I’ve become more focused in what I want, and adult toys are more expensive than kid toys. These are things I would buy anyway, they’re hobby-related.
As for things that are inexpensive, but that I need, I’ve either already got them, or I will buy them soon. They’re not really great as gifts – I need them.
Buying good gifts for an adult (especially a geek) is hard.
Somehow though, my parents have managed to show a lot of foresight in their gift-giving. A few years ago, they gave me a set of silverware. Not the cheap stamped sheet metal stuff you steal from the dining halls, but good heavy forks, knives and spoons. The value of this stuff is not immediately clear until you use them. They’re unbendable, unbreakable. When I moved I left behind or tossed the mishmash of collected silverware from previous years. Cheap, broken, bent, awful. The gift of good silverware managed to improve my quality of life in a substantial way that you wouldn’t immediately expect.
On my birthday this year, my parents gave me two pairs of new Birkenstocks. My old ones are worn past the sole, and the insole is trashed, but I hadn’t thought of replacing them. The value here is immediately obvious in hindsight, but it’s a non-obvious gift to me. Why two pairs? Because my feet sweat. Two pairs last more than twice as long. These people are thinkers.
I don’t mean to say that someone buying me something I want makes it a bad gift (not at all, go ahead and buy me that stuff, I want it because I’ll use it), but that a truly great gift is something you never expected that managed to improve your life in a way that makes that list of crap you want look insignificant in the long term.