I've been using Net Stat Live! for a while, having tried a number of others.
It's great in situations like I'm currently experiencing with my supplier.
It shows your live traffic, average traffic, peak bandwidth and agregates monthly totals. It's great for keeping an eye on your monthly usage and your live speeds. It can be configured to run at startup and hides nicely in tray tools until you want to check your stats.
Best of all - It's free!
Download it here.
They have a number of other useful tools.
Their ITR Client looks good too, but I've not tried it yet.