>From the reading that I have been doing about SharePoint 2010, one of the areas that Microsoft seem to be trying to tackle is allowing people to build components that are not too resource hungry.

Whilst reading the SharePoint 2010 Server Core Class Library documentation one of the namespaces that looked interesting is the Microsoft.Office.Server.Utilities. In here are delegates which can be called to enumerate SharePoint objects. The advantage (and this is purely from the documentation) is that they enumerate without consuming too many database resources.

Another feature that I have already mentioned is the sandbox solution which allows a site administrator to deploy a wsp solution file with code to a particular site. The code that is deployed by this solution is then run in a separate process with limits on the amount of resource that it can consume.
 
With SharePoint being a shared platform which can be used by many different areas within the business implementing code which is scalable and efficient in terms of resources used is going to become more important and undoubtable be a best practice in similar vein as disposing of SPSite and SPWeb objects correctly.