Apple today released updates to Final Cut Pro X, Motion 5 and Compressor 4. Fire up the App Store and click the Updates icon.
If you don't see Motion 5.0.1, FCP X 10.0.1, and Compressor 4.0.1, click the Purchases tab. If clicking Install from there won't work, first trash your current version of the appropriate app and try again - that's what worked for me (thanks, Twitter).
The FCP X update is signifcant: media stems export, XML support, Xsan support and more.
What about Motion 5.0.1? Dual monitor support. You can send your Timing Pane or your Canvas to a second monitor (from the Window menu). But it's full frame - you can't manipulate it - and you can't send it to any monitor you wish. Other than that, it's bug fixes. Which ones, I haven't yet seen. More to come.