Re: What is the data that i should display on my dashboard?
I would very strongly recommend asking your users what they want to see - the whole point of a dashboard is to provide someone with the information they need, not the information someone in a different (and sometimes fictional) company needs.
If you don't have access to your users (executives tend to be busy...), try asking for the reports they normally use. That should give you a good idea of what information they're looking at, and you can either replicate it or build up from that.
I'd recommend you give a quick read to http://www.perceptualedge.com/blog/?p=672 , and if you plan on building dashboards regularly, I'd recommend picking up a copy of Stephen Few's "Information Dashboard Design".