USE="hal" is masked in base/use.mask, but unmasked for kde-base/solid and app-cdr/k3b in base/package.use.mask pending on KDE 4.6.x stabilization.
This is preparation for dropping the uncompressed usb.ids file from sys-apps/usbutils, which HAL relies on. Also, both udisks and upower now have blockers for sys-apps/hal to prevent overlapping features. -Samuli
