Best desktop deployment strategy

Dear friends,
I have more than 10.000 desktops (Windows +Non Windows) with 1000 of different application, network connection from 10MB to 100MB. Till now they were all in 20 different domains and each Admin had its own rule of thumb to deploy the OS and applications.
Now all 1000 applications and OS have to be centralized deployed. Application should be properly grouped the network connection with 10mb speed cannot upgraded in this year.
What would be best deployment strategy?
What are the best tools/software in market?
Is there any overview of best deployment technique?
Thanks

Shashi