XML Document Design (Attribute vs Element)

[Shurijo]

Thanks for the help on the other post. Now I have a design question....

I have noticed that some XML authors use attributes and others use elements. Is there any guidelines you guys use to make your XML documents?

I have been using elements for long text values and attributes for everything else (like example 3). But I noticed that a few people use elements and/or attributes for all items, etc.

example 1.....
<user>
   <firstname>John</firstname>
   <lastname>Doe</lastname>
   <category>4</category>
   <gender>1</gender>
</user>

example 2....
<user firstname="John" lastname="Doe" category="4" gender="1" />

example 3...
<user category="4" gender="1">
  <name>John Doe</name>
</user> 

P.S. I think this is on VB.NET topic discussion, but it may fall under database topics. I would like to pick the brains of some of the VB users here, since they have helped me with other stuff in the past.