Application pool for each SharePoint (WSS) site?

After a long time I'm returning with some SharePoint administration and deployment topics.

One of them is Web application pools with SharePoint. When creating more top level sites with each its own application pool, you can seriously think about how this will affect the server performance.

With around 50 SharePoint sites (and app pools) running we've increased the page file from 1 GB to almost 4 GB.

So planning here is very important. Think about how many web applications you'll need. If you'll need many, think about grouping web applications to application pools.

The difference in performance is very obvious.

If anyone has similar experience, I'll be more than happy to read about it in the comments to this post. :)