Founder of Digg.com
Geek gift: Amazon's Kindle is an amazing device. Because e-paper reflects light like traditional paper, there is no eyestrain. It also comes with built-in, free high-speed Internet access so you can download books from anywhere on the go. It's a bit pricey, but for a bookworm it's a pretty cool device.
Ultimate invention: Wireless power. I read about a recent experiment at MIT that transferred power over a two-meter distance, powering a 60-watt lightbulb. Imagine a city blanketed in wireless power—I'd be the first to toss my laptop’s brick power adapter.