Many people ask me about the differences between Team System and Visual Studio, and what is Team Suite. When I start my explanation and including informative data such as the Team foundation I can see their eyes roll inside their holes, and their face start changing colors.
Here I'll give short introduction to this subject.

First, I'll start with the Team System - there is no such product, stop using this name, I like to call this a framework or package.
You can see in their product information center: there is no susch product!

The 3-Team Editions: 

1. Team Edition for Software Developers- includes code analysis, performance  tools, code coverage, unit testing, Microsoft says that it also include the Visio and UML modeling, I didn't find such thing yet.
2. Team Edition for Software Architects - includes Application designer, Modeling tools, full synchronization between code and design elements, this edition not include neither code profiler/analyzer nor unit testing, web testing.
3. Team Edition for Software Testers - includes tools for testing and manage the result, you can connect between the test, failure and the code that reproduce this, this edition not include application designer, but the strange one is that this one not include the code profiler and code analyzer.

The all three includes of course the Visual Studio (Professional) with all the programming languages inside.

After we explain the core editions of Visual Studio 2005, lets mix it all together to one package called Visual Studio 2005 Team Suite. 

Pay attention to the colors, this colors indicate the original colors from Microsoft products.

There is still one product we didn't talk about, the Team Foundation Server (TFS), this one includes management tools, full integration with the client products (all roles of Team Suite). TFS is a server side product which combine together all the relevant data of your projects, such as bugs, code, testings, performance data.

Remember the Team system? now I can explain to you why I call this one framework, when you are working in a company and you have both programmer testers and you want full integration you will probably need the Team Suite and the Team Foundation Server this two products called Visual Studio Team System, but still you will buy them separately.