New goodies in iPhoto 6.0.4 include a variety of new Greeting Card and Postcard themes for use with Apple print services, including invite and thank you card designs for summer parties, weddings, birthdays, etc.
Aperture improvements seem more under the hood dealing with overall reliability and performance. I downloaded both of the updates they are running fine on my Mac. You'll need some bandwidth however. The Aperture update is 14.2 MBs and the iPhoto 6 download is 36.4 MBs.