Spent almost an hour trying to get the new Keynote, Pages and Numbers to work. Having updated all three all crashed upon lunch. I tried deleting and reinstalling each application, to no avail. My issue came down to fonts. The crash was the result in a bug in each application,

Application Specific Information:
*** Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '*** -[__NSSetM addObject:]: object cannot be nil'
terminating with uncaught exception of type NSException
abort() called

I can only assume that one of the fonts installed, was failing to load and as a result a nill was trying to be inserted into the font set being loaded up. Anyway here is the solution that worked for me.

• Open Font Book
• Select the File menu
• Click Restore Standard Fonts ( Don’t worry you shouldn’t loose any custom fonts they are merely moved )
• Open your applications to make sure they work.
• Finally go to Users->Library->Fonts(Removed)
• Drag all of these fonts back into Font Book to restore your Fonts
• Ensure your iWorks Applications are still working

Hope this helps someone and saves you the pain I have just had.