What’s Hot and What’s Not with Resume’s?

When creating various resumes as a independent contractor is it wise to add all the companies you are working under for a project?

Example
Centra Solutions contract to Webelectronic
Nov ’07 to Present
Los Angeles Ca
Systems Admin

Or

Name of Staffing Firm
Nov ’07 to Present
Los Angeles Ca
System Admin

Any suggestions I’m experiementing with
entering only the staffing firm I’m contracting or subcontracting with?

Thanks,

TechG