Just do lots of overnight downloading and lots of everything when the speeds are not capped.
No tethering at all. Lots of streaming media and downloading of large files.
Updates, iOS firmwares, Xcode, things from my remote server, disk images, and other misc stuff.
Are you near any wifi or are you on location without wifi a lot?
About 220 kilobits per second. Slightly faster then EDGE with a ping time of about 89ms.