For writing, almost anything. For spreadsheets, unless you need Excel plugins, again, almost anything. For project management? There are a good couple tools around.

They don't need Office. They are just used to it, much like accountants are used to their 12C's

The problem here you see is that people don't want to spend time learning computers if they can avoid it except for browsing.

Now most students are being trained to use Office at school.

I use to see the world from an "Open Source" programmer's point of view: "You have the choice to use OpenOffice". But then after I saw the reality for a while, things start to sink in and it becomes obvious that people don't want to be liberated the way I thought they ought to be.

People are OK with MS Office. It becomes a piece of software that, no matter how hard geeks want to argue about the Pareto Principle or not, will stood the test because people were being trained regardless its complexity.

So yeah, from "feature/functionality" perspective, there are alternative. But from skill-wise, willing-to-learn aspect, there aren't until Universities and/or schools start teaching young people to use something else.

OTOH another argument is: you don't need the other alternatives if you have Office.

Well... Tablets are kind of changing that. We'll see in a couple years if students will insist on carrying their notebooks running Windows.

Even if they won't do that, they'll go to their lab to do the must-do assignments using MS Office for certain type of assignments.

A person close to me is currently taking Accounting courses and calculator + paper do not cut it. You need Excel.

No. You need a spreadsheet. Excel is just the most popular one, much like the 12C is the most popular business-oriented pocket calculator.