I'm going to edit out the strikethrough because other people may have the same type of question and it makes it difficult to read. I would like to answer a question about user CALs, though. 50 user CALs could cover either 25 users each per 2 servers - unless you are using Active Directory - in which case it covers 50 users for any number of servers in the domain. When you use Active Directory, your CALs are licensed per domain, not per server.
This setup could have also been resolved with SBS 2008 Premium. You get Small Business Server 2008 (server 1, this includes Exchange) and a full license of Server 2008 Standard (for whatever else you needed) and can be licensed for up to 75 users total.
Essential Business Server and CALs also work, but they provide a broader spectrum of services than just Small Business Server does and might be overkill for a small business, depending on their support needs. If you have a 100% Microsoft shop, its a great solution. I personally prefer a blended approach.