Without further ado, I present The Abstracted Engineer's 2009 Holiday Gift Guide!
1. The Emperor's New Mind, by Roger Penrose. A well-thought out argument that human consciousness is non-logarithmic, thereby making it impossible for standard computers to successfully imitate the human psyche. Good reading for any cerebral dork.
2. Mututoyo Digital Calipers, via McMaster-Carr. Probably the single greatest tool in the history of ever, the digital caliper is like a hyper-accurate ruler on steroids. No engineer can exist without one.
3. A dozen neodymium super magnets via United Nuclear. Your engineer will squeal with joy when you present him with a half a dozen of these, and tell him to go the garage and not come back until he's built a rail gun.
4. Kickin' Bot: An Illustrated Guide to Building Combat Robots, by Grant Imahara. Grant is the well known smart kid on Mythbusters. Whenever the Mythbuster team needs something requireing brainpower to build, they turn to Grant. He also won the Discovery Channel show "Battle 'Bots". His how-to guide is fun reading.
5. 9480WK Breadboard, via Amazon. I can only imagine the world in which Tesla had one of these handy, to build his free-energy car or his death ray.
6. A Hummer HX, for that engineer going through a mid-life crisis.
7. Tickets to see a Japanese fluorescent light fight. I kid you not.
8. Alienware Area 51 ALX desktop. Dell's version of Lexus is Alienware, where you can buy obscenely expensive desktops for your engineer who likes gaming. See gift 9 for a better gift idea, however.
9. Gift card to Newegg.com to buy all the components in the Alienware Area 51 ALX at half the price and build it him/herself. Nothing says "I love my engineer" like enabling their lust to assemble components into a working...something. And better than paying ridiculous overhead at Alienware, you can get a full list of the ALX's components and let your engineer build the same thing...or give the engineer a gift card equal the cost of the ALX, and see how obscenely powerful of a computer they can create.
Warning: a computer that expensive, bought and assembled from parts from Newegg, will probably obtain consciousness and try to take over the planet. Scratch that, see gift idea #1.
10. And least but certainly not least: this wins the all-time "why didn't I think of that" award. Get one in English and one in metric. And then throw away that disorganized box of sockets, the socket strips hanging on your pegboard, etc. and enjoy a clutter-free life.
Disclosure: none of the provided links will make me any money, hot-linking to Amazon implies a bias (READ THIS GLENN REYNOLDS YOU VAMPIRE) and so I do not do it. These are honest, real links without my personal gain (other than that I want someone to buy me these things).