WWDC has been used as a platform for new products & product updates about half the time in the last 15 years.
Based on information SolipsismX dug up:
2013: New Mac Pro, new Time Capsule, new Airport Extreme
2012: Retina MBP, updated Air
2010: iPhone 4
2009: “the new 13" MacBook Pro, updates to the 15" and 17" MacBook Pros, and the new iPhone 3GS.”
2008: iPhone 3G
2006: original Mac Pro, and Xserve
2005: (announced Intel transition)
2003: first G5 PowerMac and external FW iSight camera
Thanks for collating that information.