“2600, The Hacker Quarterly”
2600 is a magazine by, for and about hackers and hacking. If you immediately think that means the jerks who put spyware on your computer and stole your credit card number, you've confused "hackers" with "criminals". Think Matthew Broderick's character in WarGames.

“MAKE”
MAKE is about building things and being creative with technology. So far I haven't actually built any of the projects but I enjoy reading it.

“Scientific American”
I read SciAm to stay on top of news in the science and technology fields that's sometimes ignored or not covered by major media outlets. I tend to skip over the soft science (biology, genetics) but enjoy the physics, environmental, astronomy and the regular columns and reviews.