I'm not sure I understand this reply. If a system is installed from 4.4, and regular updates are done, it's my understanding that there is no compelling reason to download and install 4.5; that the release of 4.5 is just to change the starting point for new installs.
If you run regular updates on a 4.4 box, once centos 4.5 is released, your 4.4 box will be updated to 4.5. You'll simply need to reboot after the update.