If you are the proud owner of a Kindle 2, I suggest downloading the latest firmware upgrade, which just became available last night.
Now I haven't heard of a ton of issues with the Kindle 2, but what this upgrade does seem to fix is page refreshes and ghosting issues. Some people have reported more eye strain from the Kindle 2 compared to the first model because of its lighter text, but this isn't something that will be changed in this update. . . maybe next time.