First of all client-server is a computing model, meaning there are other models of computing. The main alternative to client-server is peer-to-peer. Try this analogy:

When you go to a restaraunt, you are the client. You request services from a server. The server gives you the services you ask for, and checks in from time to time to either grant new services, refresh existing services, or properly put away the services with which you are finished. If 3 clients left, business continues. If three servers left, all the people they were servicing now have to either find someone else to service them or they can't continue working (in this analogy: patronizing) their environment.

Peer-to-peer on the other hand, is like Thanksgiving dinner. You are both providing services (you bring one or two dishes) and requesting them (you eat the foods that others brought). When you want your glass refilled, you refill it yourself. If you want something more to eat, you go get it. No one person is in command nor is any one person completely reliant on everyone else. Everyone is essentially equal.

Both architectures have advantages and disadvantages. Peer-to-peer is easily setup and runs on the vanilla PC's that we all have at home. Unfortunately, it isn't the most secure system (I wouldn't put tax documents on a computer configured for peer-to-peer).

Client-server generally is more secure, but more complicated to setup and maintain. The server component can be commodity hardware, but realistically can run between $5,000 - $500,000 depending on what you're running. The clients in your client-server environment can be the same vanilla PC that you have at home, but it will probably be running Windows 2000 Pro or XP Pro instead of Windows 95/98/Me/Xp Home edition.

In a nutshell, if you want to share a printer among the 3 computers in your house, go peer-to-peer. If you are setting up a production LAN that will be processing millions of financial transations per day and need a stable, secure, professional environment, go client-server.

Did I answer your question?