Update: Since this blog was written, Adobe Reader has been updated to 10.1 More details here.
Adobe Reader X is now available for download. You can get it here. If you are using Reader X or Acrobat X, also make sure that LiveCycle ES2 is on SP2.
There has been significant security-related enhancements to Reader in version X. One of them is “Protected Mode”. The details are available in the following links:
Also, see MAX 2010 presentation titled “Sandboxing Adobe Reader: Protected Mode” by Suchit Mishra, Lead Security Researcher at Adobe.
Public forums for discussing Reader-related issues and sharing solutions is available here.