Patch Management

I have just recently started on a project for implementing a patch management solution. So far these are the products i’ve learned about:
Microsoft WSUS (Upgraded SUS – not yet released)
Micrsosoft SMS
Shavlik’s HFNetCheckPro

I am with a company of about 300 employees, and 200 servers (DMZ’s, extranet, intranet).

Any help would be appreciated.