Help, choosing a knowledge management system

Hello,

I have been charged with converting my companies old media wiki system into a CMS system. Our IT department have supplied Drupal, CMSmadeeasy and typo3. My knowledge is limited but from playing around, looking at sites and using some Drupal books, Drupal seems the system that we would most likely use. I need to make sure it fulfills the following requirements, some I am sure it does and others I am not so sure of so was wondering if anyone would be able to give me a guiding hand.

The key questions I need help on are;

* Is it simple to create pages and link from one subject to another? We often breakdown parts of the processes that our company performs into seperate pages so that is not too much information on each page. This is simple on Mediawiki, is it the same on Drupal?
* Is it possible to have drop down menus? It seems nicemenus would be able to perform this?
* On the home page we also want to have a "box" containing tabs for each department, when a tab is selected it shoes links relevant for that department, is this possible?
* Easy to manage the layout and management of the documented processes?

Any help or advice would be really appreciated. As I say I became very proficient on MediaWiki but programming php and html are beyond my knowledge levels at the moment. My IT dept would take care of the nodes and modules etc, I just need to make sure that as the person who manages, writes and uploads the content and is charged with the responsibilty of communicating everything to each department, that Drupal does what it needs to. The company is only about 300 people and all on the one site so know need to worry about communication to the masses.

Many thanks for your help

Mat