I beleive nationalism was by far the biggest effect.  Its so powerfull it still factors into our lives and the entire mindset of many peoples is changed. 

As for Napoleon, definately an underminer of the revolution, and a waste of miliary genious.

What do you think was the major cause of the French Revolution? Where are a number of possible choices and my choice:

1. France's dire financial situation that was provoked by the 7 Years war and through supporting the American Revolution.

2. The Influence of the American Revolution and the enlightenment thinkers.

3. The lavish spending of Louis XIV and the Kings before him.

4. The discontent of the nobility.

I hope I am not forgetting any but I would have to say that it was France's financial adversity that provoked the Revolutionaries. It is without question that if your people cannot feed one another, they will revolt. Remember Marie Antionette's famous line: "well let them have cake." Also I think the economic uncertainty lead to the discontent of the nobility, which created interest in the enlightenment thinkers. 

Fact or exaggeration? The French revolution changed the course of history more so than any other single event.

Exaggeration.  More than sliced bread?  More than electricity?  More than fire?

Good question but it's too broad a statement to deal with as it stands.

Limit it perhaps to European history?  More than anything in Greece or Rome?  Perhaps since the 10th century.  More than the birth of  Henry the Navigator?

I still think you need to set parameters on the question - yes it was an important event - relative to??? - but cannot stand alone.

On the other questions - it's been a while since I read up on the period - I'll need a refresher.

Let's see...

I think the French Revolution is one of the most important social and political events in history.  Just imagine if one of the most powerful nations in the world today overthrew its government and eventually went on a 25 year bid for world hegemony.  The world afterwards was so radically different, the Americas got their independence, America was much larger, nationalism came about to affect the course of society ever since, secularization and republican values were brought to the forefront of world politics, and the list goes on and on.  I would say that the French Revolution is just as, if not more important than, the World Wars this century.

I would say that you can't really understand European history to any great extent without having a decent knowledge of the French revolution.

It seems to me not enough distinction is being made between the French Revolution and the Napoleonic Empire.

The revolution itself put into effect notions of liberty(and equality and fraternity) that already existed: it didn't give birth to them. Nor did it promote nationalism: in fact it was anti-nationalist, and ideological - the early military campaigns of the 1790s were designed to spread that ideology to neighbouring countries.

In both these ways it was really very similar to the Bolshevik revolution. It was also similar in that it was very soon corrupted into a grab for power by a ruling elite, ending with degeneration into tyranny under Napoleon and Stalin.

That said, it seems to me the most concrete example of a long-lasting result of the whole episode is the influence the Code Napoleon continues to have on legal principles and jurisprudence over much of Western Europe (and Louisiana ).

but don't forget that before the revolution people were fighting for their king, but revolutionary France did fight for it's nation (well, later for Napoleon but you know what I mean..)

Apart of course from the Dutch and the Swiss and the Venetians and one side of the English Civil War, and something like half the population of France in the 16th century. And the pre-Imperial Romans, and the Athenians, and....