You might want to make a plugin engine aswell.
In case you want to be saved for the work, I can give you the one I coded, which, like most plugin engines, uses hooks.
The plugins are made using classes, and you have 1 parameter for additional stuff, in the execution function, which is then returned (for adding stuff to pages and such).
If you made/use a plugin system, the Online chat/Shoutbox, Forum, Downloads, Donation System, Best Videos, Map Overview, Clock, should be made as plugins, because they aren't neccesary for every server owner, and then the server owners that wants those features, would just install the plugin (maybe as a package).
Anyway, I have another suggestion:
Automatic Update Check - Everytime you visit the admin panel, per session, it should connect to your website, and check if there's a new update. If there's an update, it should give you the oppotunity to download it, and install it (using WinRAR .exe files maybe?)