(Well, not too much of a surprise in that there were no significant changes from beta 5 to the release candidate, but hey)
Things have gone well for this release at the end, and the 5.0.1 release is live and ready for download. So, enjoy!
What's next for OmniGraffle? Good thing you asked, because I, as product manager, have the answer to this question. We got a fairly hefty set of changes to the Japanese localizations a little too close to the final release of 5.0.1, so we'll be turning this right around with a 5.0.2 beta very shortly. OmniGraffle 5.1 looms in the far distance, and there will be lots of things to peruse in that release.