I'm surprised I didn't know this one already: http://interactions.acm.org/

Interactions is a bimonthly publication of the Association for Computing Machinery (ACM) and is distributed to all members of SIGCHI. Lots of interesting things in here and broader than I expected, e.g.:

• Designing from the Inside/Out
• Into the Groove: Lessons from the Desktop Music Revolution
• Merging Design, Business, and Sustainability: The Designers Accord
• Take a Chance on Me: Using Randomness for the Design of Digital Devices
• The Convergence of Architecture and Interface Design
• http://interactions.acm.org/index.php