TrafficBot is the only network usage monitoring app you will ever need.
Features:
- Simple and elegant UI.
- A gauge in the menubar to indicate your usage level.
- Monitor total usage in a rolling (very nifty feature for college students!) or a fixed period.
- Notify you when usage reaches your limit.
- Run scripts or open any documents or apps.
- Log and graph your usage.
- Graph is detachable, so you can always see your current usage.