[Brian]

Do you have syncing turned on? If so, the app will do a sync before quitting, which could explain the delay.

If that's not the case, the answer to your question re: database size is "it depends". If you have files attached - either by dragging in from the finder or from using the Mail Clip-o-tron and/or Clipping Service - then 8MB probably isn't that big.

If you *aren't* attaching files or using clipping, though - if your database is just actions you've typed into OmniFocus, then 8MB starts sounding bigger.

If you're reading this far into the post, I'm assuming you have sync turned off. If you select File -> Move Old Data to Archive... from the menu bar, how many actions does OmniFocus suggest moving to your archive?

If that number is large, you may want to try that. Quit, re-launch, and re-quit OmniFocus. Is the shutdown time shorter?