List of nodes limited by last node created from each user
Views 3 has the perfect new relationship type for this "Obtains a single representative node for each user, according to a chosen sort criterion."

To do this, begin with a new view which is a list of Users in fields format. By default you will see a list of usernames. 

Then add a relationship 'User: Representative node (search for 'represent' when adding the relationship. You can choose the sort criteria as perhaps 'updated date' order by descending.

You can now add extra fields using the related data - such as 'Content: title' and 'Content: Updated date' using the relationship 'representative node' for each new field.