I'm curious what the requirements are for Excel Calculation Services in Sharepoint 2010. I found an architecture document but it doesn't list out the specific requirements. (architecture I understand that you can install all the services on one server but it isn't recommended. It then talks about how you can scale up the application servers, and web front ends. What should the hardware look like for both the application server and web front ends? Do I need to setup a standalone box for each application server?
Microsoft has a bunch of capacity planning white papers for SP 2010 available. One of them covers Excel Services.
Unfortunately, it isn't as simple as "you need a server this big" - it is more "depending on how many users, how many documents, how big the documents are, what phase of the moon, etc."
Here is a link to all of the white papers: