XSLT is just one method of templating. It is also just one piece of a complete MVC framework, where templating being the View component. XSLT is a great technology, but it's slow and not a first choice on building a scalable web site.
Research on MVC frameworks to see which one fits you best. e.g. ASP.NET MVC, Ruby on Rails, CakePHP, Catalyst, etc.
