If I have to choose between them I would learn the French because Philidor defense is a little bit unambitious and the Petroff isn't forced (if you answer e4 with e5 your opponent is able to play kingsgambit, vienna game, bishop game etc.). But you should maybe think about the Caro-Kann defence because it's a good solid choice and quite logical.
Easy to learn defense for black
Vielen Dank. Ich will Caro-Cann lernen. Ich habe gerne diesen Schutz gespielt. Aber hatte ich keine Erfahrung für lange Zeit. Vieleicht soll ich diesen Schutz ab Anfang lernen.
Könnten Sie mir bitte helfen? Welcher Bucher des Caro-Cann empfhelen Sie?
Es ist auf jeden Fall eine kluge Entscheidung die Caro-Kann Verteidigung von Grund auf zu lernen. Ich kann ihnen auch gerne das ein oder andere Buch über Caro-Kann empfehlen, in welcher Sprache sollte es denn verfasst sein?

Ok, I will ignore comments 3 and 4. I think the French is a good choice. If you don't want to study a lot of lines you can directly play Rubinstein variation (3. ...dxe4), valid against both 3. Nc3 and 3. Nd2. So you practically only would have to study the advance (3. e5) and the exchange (3. exd5) besides that.

Some of the moves/ideas in the French defence are fairly thematic, especially if you play 3Nf6 in response to 3Nd2 and 3Nf6 in response to 3Nc3. It is not too difficult to learn upto move 8-10 in any of the main variations by which time your opponent would probably already have left the book anyway.
It will be easier than Caro-Kann. It is also more counter-attacking than the Philidor, Petroff, or Caro-Kann if that is your particular style.
French is nice because it's solid so easy to be consistent with it. And you still get some practice in open positions in some lines, especially the exchange variation (which is very common at low levels!)

What you need to learn in e4 e5! can be explained easily:
And the Italian, Scotch and Ruy:
To the stronger players: White might have an advantage (small) in these lines, but I think that it's a fine position. There is not so much to remember, and if you play logical moves, you get a playable position. It is worth analysing the games (even in blitz) when you try out a new opening, so you get some ideas of what is happening and what are logical moves and what are not logical moves.
2Sheldor66 Personally, I prefer books in English. However, I can read also in Russian and German.
2Pulpofeira This is very interesting idea, how to simplify french defense. I am going to check it. I will thank you if you could recommend me some thematic books.
2Username333 and ViktorHNielsen I agree that 1. e4e5 is the strongest moves in chess. But in this case you should study a lot. Except King's gambit, you have all these weird staff like Bishop, Ponziani, Wien opennings. Although a lot years a go I had very beutifull Albin Countergambit game from black side(all my moves were "from book") without ever reading about the theory of this openning, all i knew was only 2 first moves, others were just natural, still I am not sure I could do it again :), because I still do not know it's theory and this oppening has very wide theory. In addition you should study Ruy Lopez with a deep and complicated theory. Even Italian may be not so "slow game". In my level, Ewans gambit may be very powerfull weapon.
All I really wish is to have one/two openning for white and for black side and then to move study more tactics and endgame.
There are some good books about the Caro-Kann but I think that this one matches your prefernces most:
http://www.amazon.de/Grandmaster-Secrets-The-Caro-Kann/dp/1904600611
Grandmasters secrets: The Caro-Kann
This is a link to the german amzon site (the book is nevertheless in english), because on amazon.com was only the kindle version avaliable.

If you would like to look at some videos on the French defence. Kingcrusher has a good overview of the French defence at:
https://www.youtube.com/watch?v=DeaRrjTGMRE
Tatev Abrahamyan also has a number of videos on the French defence at this site. However, I have no idea what they are like.
If these videos are too advanced for you then you should be able to find something more basic on the internet.

the kings indian can be used v many openings
why not study this you will not always face 1 e4 at chess.com and a kings indian covers alot of white first moves
Hi all,
I am beginner and I wish to pick up one defense for black as response to 1.e4, but I do not wish on my level to spend a lot of time on openning studies. In the other hand, I do wish to get a solid defense.
I am trying to choose between Petroff, French and Philidor(exchange variation). What would you like to advise me?