Geek-themed stickers aren't hard to come by. Few sets I've seen are as good as this collection from the makers and tinkerers at Adafruit Industries, though.
Being from actual engineers and hobby builders, the set ditches the comic book and sci-fi clichés common in similar sticker collections. Instead, we get something that reflects what most real-word geeks likely busy themselves with -- you know, repairing bicycles and tinkering with breadboards. At least, when they're not busying themselves with comic books and sci-fi, that is.
The stickers, which can be peeled off individually, measure 2 x 2 inches each, with the entire sheet measuring 11.5 x 14.5 inches. Notable designs include an oscilloscope, a 3D printer, a microcontroller, a soldering icon, a quadricopter, a Tesla coil and even an Ada Lovelace avatar. All stickers are glossy and printed on vinyl to last you a long time.
While these would, obviously, look good on a laptop or a toolbox, Adafruit is trying to push it for use as some sort of badge for maker workshops and classrooms, too. You know, like you get a soldering sticker if you master that skill or an HTML5 badge if you manage to convert your Flash website into the new browser standard. Or something like that.
You can get the stickers (33 in the set) from the Adafruit website, priced at $35.