They each ship with some different tools that are specific to the version. The following links may help. Also take a look at the download datasheet link on the below links.
http://msdn.microsoft.com/vstudio/teamsystem/products/arch/default.aspx

http://msdn.microsoft.com/vstudio/teamsystem/products/dev/

For more technical info see:

http://msdn.microsoft.com/vstudio/teamsystem/reference/technotes/

http://msdn.microsoft.com/vstudio/teamsystem/support/faqs/default.aspx

http://msdn2.microsoft.com/en-us/library/57b85fsc(VS.80).aspx

http://msdn2.microsoft.com/en-us/library/47f7hz7y(VS.80).aspx

Thanks
Brian [MSFT]
Microsoft Developer Support
This posting is provided "AS IS" with no warranties, and confers no rights.

Hi M,

The Architect version contains the Distributed System Designers as follows:

Application Designer, System Designer, Deployment Designer, and Logical Datacenter Designer

These designers allow you to design and validate systems for deployment. You can compose these systems from ASP.NET Web service apps, Windows apps, external Web services, databases, and generic apps. You can add multiple uses of these apps (and configure each of them differently) to different systems. You can then validate these systems against logical datacenter configurations to see if they will successfully deploy.

Brian's posted some links that I was going to post, but here's one more: 

http://msdn.microsoft.com/vstudio/teamsystem/products/compare/default.aspx 

IMHO, if you are a company that has 5+ developers, a project manager, a division/department manager, and a admin assistant, then you can use the team development system.

Otherwise, save yourself some time and use some other more flexible development methodology that does not enforce tons of overhead.

All of the team development systems, case tools, code generators, and catchy new terms to 'enhance' software development will never be a substitute for good communication in a development team.

Just my two cents.