Back in the day it was easy, 1 or 2 major product announcements.
However, for the past few years we have been making so many revolutionary product announcements that it's getting hard to keep things straight. The fact that I' getting older does not help matters much ;)
2008: Foo Fighters, Force.com Sites
2009: Black Crows, Sales Cloud 2, Service Cloud 2, and, of course, Chatter
2010: Stevie Wonder/Will.I.Am, Database.com, the Heroku acquisition and more Chatter enhancements
2011: Metalica, The Social Enterprise, Social, Touch, Mobility and expansion of Heroku’s capabilities
2012: Red Hot Chili Peppers, Business is Social, Work.com, Marketing Cloud
2013: Looking forward to Green Day and The Customer Company Revolution