I still don't know. This is the first time that I'm voting ever, and I want to vote for whoever is best to get rid of Sarkozy in 2012. And if you ask, despite my wish to vote for the best and not just for the "less worse" : yes, these elections in France are seen as a test for Sarkozy and nothing else. I'm progressively changing my mind : before I kept wanting to vote for the best and saw no one good, so no vote ; now I see things from the strategic point of view.
But to give an answer : probably something like Green, Centre or Socialist.
EDIT : BTW, after all the buzz from the trial of the Pirate Bay in Sweden and the (still going) vote of the HADOPI law in France, I'm eager to see how good the Swedish Pirate Party will do.