I am a technical geek and have been using Linux since 0.9x
I am of the opinion that the first company to create a Minux3 based kernel, plus integrated VM controls, with separate user spaces will consolidate the server market for Linux
The killer app for Linux will be a complete desktop suite including a DB based email server and email client with integrated calendering (Exchange/Outlook). This will also likely need a DB based AAA server to replace the function of AD. I see a possible path by converting TACACS+ or something similar.
It's going to have to integrate with the phone system too, if it's going to go toe-to-toe with Exchange.