What versions of Windows are currently the most popular

Question

Does anyone have a ballpark percentage breakdown of Windows versions currently being used out there?

For example, 60% are using Vista, 30% XP etc etc.

We are currently building an installer and we need to know what will give us the most coverage. What we are particularly interested in is the prevalance of .NET versions as our application has a dependency on .NET 3.5 SP1.

Answer 1

Take a look at w3schools browser stats.

Edit:

Since a lot of people seemed interested in this, I plotted the stats as a graph:

alt text http://lanfear.c0la.se/~emil/osmarketshare.jpg