Microsoft has announced a new, Microsoft Certified Master technical certification level that will be added later this year. Initially, this will be available for Exchange Server 2007, SQL Server 2008, and Windows Server 2008 Active Directory.
I have always been a fan of vendor certification, especially from Microsoft. I think that getting certified shows that you have some extra initiative, and that you care about your career. You also tend to learn some aspects of the product that you might not be familiar with from your normal, daily work.
On the other hand, certification is not a substitute for experience and knowledge. I know many developers and DBAs have an attitude along the lines of "You can either code or you can’t code, and I don’t need a certification to prove it". There is definitely some truth to that statement, but at the same time, it certainly does not hurt to get certified.
I have found certification to be helpful in getting interviews and even during technical screening interviews, since the person interviewing you often assumes that you have a high level of knowledge before you even open your mouth.