>I am writing a 4 Tier system using data centric objects that call Sprocs on a SQL server. I plan to have one Class for each file. The question is should all the classes be in one dll or should each class have its own dll?

We can have a long discussion on what is the best way to do it!

I normally consider layer and distribution when grouping classes in DLL components.

Presentation layer classes that will be installed on the client computer = 1 DLL.

Presentation layer classes installed on a server = 1 DLL.

Business logic = 1 or more DLL.

All data layer classes = 1 DLL. This later DLL will be as near from the database engine as possible.