DS13 is also an electronics nut. The kids shows us how to program our cell phones, ways to get the DVR to work without skipping and how to download music to our iPods. I have to say that with his passion for techno stuff, I have a hard time finding a place to put it all. So, anything that has to do with storage is always good.
I also ordered retractable ear buds for his iPod (he complained about the long wire getting tangled when he's not using the unit).
For his computer stuff, I got him some storage units. Drawers for the CD/DVDs, boxes for all the USB-powered stuff that he isn't always using.
I got him a headset for his computer because he likes to do online gaming and the microphone he had just isn't cutting it.
I'm going to set up an iTunes account for him. You can set one up that allows a set dollar amount to be available to your kid each month for as little as $10/month. What's nice is that you can limit it to however many number of months that you want. So, if you want to give just 2 months of music, you cancel the allowance after 2 months. An alternative would be to buy him an iTunes gift card for a minimum of $15.
I bought a spindle of CD-R's for burning music. To be honest, for the most part he uses his iPod for portability but there are times when he wants to play the tunes over a stereo system and that's when the CDs come in handy. You can burn your iTunes to CD an unlimited number of times.
I got him a program for making CD labels and a supply of labels. It will make the CDs that he burns look a lot nicer than just using a Sharpie on them.
You could get him a subscription to any online game he might be playing or to XBox Live if he's into that.
I bought a disc repair kit for his scratched game CDs.
We already have a GameFly.com account but if you don't, you can give gift cards for them, too. It's a great way to try out a game before you decide to buy it and often you can buy the exact used game that they sent to you. Gift certificates can range from 1 to 6 months and they also have a 12-month certificate.
You can probably find a ton of things just by browsing your local
Best Buy store. DS would live there if I let him.