Ideas on IT (Infrastructure) vendor selection / How to select an IT (Infrastructure) vendor

This post is about a business aspect of IT Infrastructure. IT vendor selection process is becoming more and more complicated with technology advances and stiff competition between vendors.
Here is sample process I used to pick and choose an IT infrastructure vendor while I was working for a Telecom client.

Architecture Suitability Criteria
 Architecture of the Main Solution
 Architecture of the Backup Solution
 Architecture of the DR Solution
 End of Life (EOL) and End of Support (EOS) of systems
 Platform and System Familiarity

Vendor Suitability Criteria
 Technical Support
 Human Resource pool (Technical)
 Reference Sites
 Past experience with us

Commercial Evaluation Criteria
 Hardware and Implementation
 Maintenance (5 years NPV)
 Implementation Time
 Support & Maintenance Mechanism
 Support for Version Upgrades and New Modules