I'm especially proud of being part of this release, as I was involved in coding up two very user-visible pieces - the Authorization Dialog and the Calendar Drop-down. Not only is the shell super-duper hot looking (making GNOME 2.x vintage desktops look like Windows 95 more than ever), it is a true pleasure to use. One that grows on you. One that makes you never go back.
The best part about this release is probably how re-energized everyone working on GNOME 3 is. It is important to realize that 3.0 is only the beginning and that we have tons of stuff lined up for 3.0.x, 3.2 and beyond. I'm especially psyched about the prospect of making the desktop shell integrate nicely with the many Web Applications that are in use today. Myself? I'm already busy working on improvements for 3.2 - for the authorization dialog we want to present better strings to the user (e.g. including name of app in the dialog and what object the authorization is about) and for the calendar we want Locations (and possibly weather too) in the drop-down. And ideally an easier way to make the shell show e.g. your Google Calendars if that is your calendar application of choice.