Whether you are implementing an application that stores secrets on your machine, to anything such as using WS-Security or Secure Sockets to make your Web Service or Web Applications secure - the answer is YES...YES...YES!
We are living in a dangerous world, where one incorrect security decision could cost your company or even you, your livelihood.
Check out the following fantastic Cryptography Web Cast:http://www.microsoft.com/uk/technet/itsshowtime/sessionh.aspx?videoid=17
This will be time well spent...