We continue to add features to the declarative web test model that will try to allow you to stay in the web test editor and only go to code for custom rules, plugins, etc.  Prior to VSTS 2010, if you wanted to do any real branching or looping in web tests, you would have to go to code.  In VSTS 2010 we have added branching and looping into the declarative web test model.  Check out this great blog post by Chris Patterson for a complete description of the feature: http://blogs.msdn.com/chrispat/archive/2010/01/10/branching-and-looping-in-a-declarative-web-test.aspx