Newly created reports should default to the time zone the server is configured to at that time. In order to change the existing reports you will have to edit the reports settings.
On the reports tab choose "edit properties" for each report you want to modify. In the "Time Selections" section you will have to edit each entry to use the correct time zone within the "Time Navigation Rules" section.
Hope this helps!
Yes, i can go in and set the timezones in each of the pre-defined reports, it seems a little odd that I can't set the default though, I'm going to have to go through the 16 predefined reports and edit each timezone I guess.