[pjp]

OmniGraffle queries your default printer setup upon launch, and something in the drivers is taking a very long time to respond. You're likely to see similar delays when bringing up the page setup dialog in other applications. You may want to contact HP to see if they have made newer drivers available, or if they recommend removing, then reinstalling, the drivers for your printer.

Also, choosing a default template will mitigate this issue, since each template in the chooser triggers a separate query. If you choose a default, it'll only perform one.

Hope this helps!