keeping server hard drive space free
These areas are temporary files and can be safely removed
c:\documents and settings\username\local settings\temporary internet files c:\documents and settings\username\local settings\temp
the last two are where Windows may try to stick files of a crash dump for debugging...
These files are for server and application updates that you might want to roll back
c:\windows\$ExchUninstallKB911829$ or $NtUninstallKB938464$
Of course, it's unlikely that you'll uninstall a Service Pack or Hotfix from a year ago...
And these files are just downloads of the install files for a windows update, you can always download them again if necessary...
c:\documents and settings\username\ recycle bins c:\documents and settings\username\
These log files can often be archived off (to free up room on c:) e.g. w3svc logs
c:\program files\research in motion\blackberry enterprise server\logs
blackberry logs should be archived somewhere else...