The announcement went out today that Windows Vista SP1 beta will be released in a few weeks to a select group of beta testers and that it's expected to be released to manufacturing in the first quarter of 2008. You may be thinking, "Great, I've been waiting for SP1 before planning my Vista deployment", and there have been times in the past, I will admit, when I was a consultant or managing an IT department myself, that my advice would have been to wait and start testing once the first service pack of product X was released.
However, if you're already planning to deploy Vista, there's no real need to wait to start testing it with your applications until SP1 is available to you. Why? Because the main reason you need to test for compatibility is due to the architectural changes relative to Windows XP. Those same changes are also part of SP1, so for this reason, testing applications on Windows Vista prior to SP1 will be a very good proxy for compatibility with Windows Vista SP1.
So, the bottom line is that this announcement shouldn't derail or delay your testing or pilot. Check out the whitepaper for the details on what's included in this service pack.