The patch for this vulernability is scheduled to be released in October. Meanwhile if you are concerned and would like to prevent this attack sooner, Microsoft has released instructions for configuring your ISA to block it. The TechNet article is Learn How Your ISA Server Helps Block VML Vulnerability Traffic.
You may also be interested in what Jesper Johnansson has to say about VML attack and how to prevent it.
Security is a personal decision. For my users I'm reasonably certain that they will not come into contact with this vuln before the patch is deployed. This one is starting to spread but it's spreading slowly for now and in obsecure places.