Pre Built CMS or from scratch?

Just getting peoples opinions, is it best to build a Custom CMS for your website or use a pre-built one like Mambo?

I assume that HBH uses PHP-Fusion as its in the Affiliates

If you're expecting to learn anything, build your own.

Is it possible to create a website using a certain pre-built CMS, and then swap it to my custom built CMS at a later date? i need a simple website fast as im graduating in a week and need to get my grade to sign up.

yes id like to create my own CMS so i can learn more, but as im still learning PHP i dont have enough time to creat it before i graduate i was going make my site on a pre built CMS and then when mine is completed impliment it into my site and remove the prebuilt CMS as i will be keeping the website maintained for a while

A CMS is just a collection of files and database tables; remove those, and you can put whatever you want in its place. If you want to retain any DB info, just remove the pages and make your own interface with the existing tables (changing them as needed). For the grade, though, just toss a CMS package in place, definitely.