There is now 827 MB remaining and 79 days until the charge expires. I'm still on track to have a good chunk of data remaining.
As expected, my data usage behavior has changed a bit. For example, in the past I would send random pics to random folks at random times for no particular reason at all. I still do that, but I do consider the bandwidth I'll consume. If I am close to wifi, I'll wait and save my bandwidth. Also, I haven't tethered at all yet.
The main reason for the lack of tethering is the lack of a need. Also, using a handset with a generation better chipset has cut down tremendously on my desire to tether. Heavy web browsing and emailing on the ht-03a can be a bit of chore, especially if you having to switch between apps. Even with the extra 15 MB of real memory and swap, two heavy apps cannot be running at the same time. Always waiting for apps to reload and web pages to re-render was one reason to tether. With the Nexus One, I really have to do a lot at once to have that experience.
At this point, I am seriously considering switching to a b-mobile SIM for data, but it is still just week 2.