How Many
 

How many servers do you think I will need for a company of 100 people who will be dealing with multimedia content 95% of the time and collaborative written material the rest of the time?

It all depends on the usage. You need more memory and space since you are going to host multimedia contents.

That is such a vague question. There is so much more information that would need to be provided before someone could even give you an idea of what you might be looking at. The post above is definately the key here, usage is a big a factor in this while memory and space cannot be ignored either.

I would like to suggest that you should also consider the future expansion of your company. So, take decision on the basis of your current and future expected usage.

How many...
 

This is definately a question that cant be answered with the information given...

In my opinion, 4 servers should suffice. You'll have one for 25 computers, and if you get good storage and RAM, you should have no trouble at all.

I wouldn't really know, as I'm not so good with this, but I can tell you that my company has 30 computers and one server. Unfortunately, the server just died...