performance considerations

Hi guys. I am looking at building a server that will nee to support 1k+ concurrent users. This of course opens up some cans of worms.

- what kind of internet connection do I need for this?
- what kind of box do I need? Current plan is a Zentyal server (there will also be 10 office users), 8GB of RAM and a hex core Phenom.

too much too litle or just right?

Thanks!