Apple released their new version of the OS today. Lion (v.10.7) is available as a download-only upgrade to Snow Leopard (v.10.6) through the Mac App Store, but you should not even consider upgrading, now or in the near future. Aside from the assortment of problems that are inevitable in any new software release, Lion will not support older, PowerPC-based applications. This means things like Quicken 2007 and older version of FileMaker Pro, 4D, and Microsoft Office (to name a few) will not work and would need to be upgraded or replaced.
There will come a point when you will be ready for Lion, but you should use this time to figure out what will and won’t work and make the necessary changes to ensure the transition will be as smooth as possible. In the meantime, let others work out the kinks.
You can read a review of the new features here.