At New Relic, we use HighCharts (http://highcharts.com/). We constantly get questions from our customers about which library we use, because they like the way they look and function. Highly recommended.
Oh and I did this because i was bored: http://zestmonkey.com/charts.php
Great bang for the buck as your go-to first charting solution until you need something custom.
Showing a username is customer specific data I suppose, so I think most applications show customer specific data. Am I misunderstanding this limitation?