XML: Attribute or Value?

Hi,
I'm quite confused what I should choose.
Let's say I have a XML file for calendar.

Is is better to use
<Birthday>
<Name>Sister</Name>
<Month>8</<Month>
<Day>24</Day>
</Birthday>
or
<Birthday Name="Sister" Month="8" Day="24 />
or even <Birthday MonthDay="24.8.">Sister</Birthday>?

What's the difference?

I definately wouldn't do your 3rd idea, but there is not much difference between 1 and 2 and it's really an implementation decision. Just determine how you are going to use the data and which is easier.