What is your favorite defense to e4?

I have always wanted a good, sound, solid, yet aggresive defense to e4 besides the Sicilian.

Please tell me your favorite defense against e4. However, give one reason why you should play that opening, and one reason why you should NOT play this opening. I will not be accepting "there is no bad thing about this opening", there is something bad about every opening. 

So, please list your favorite opening with the pros and cons of the opening.

Thank you.

1...d6

Pro:Excellent weapon for drawing a higher-rated opponent.

Con:Not as good for must-win games

not my favourite opening though

1..c6

Pros: Better pawn structure and plus in endgame

Cons: tempi may be wasted activating b8 knight unless Karpov variation, where knight stays on d7

Name: Caro-Kann Defense

Thank you. Anything else? I am desperately preparing for a tournament in November, and I still do not have a good opening. @ Roecczak and Vyomo, thank you for answering, I will look in to both of these openings. @ Vyomo, is the Caro-Kann actually aggresive?

1. ...e6 (French defense)

Pros: Solid pawn structure and a good clear pawn breaks to aim for (c5 and sometimes f6)

Cons: Difficult to develop the queen's bishop

1...e5

Pros: Many sharp tactical variations. If opponent does not a sound knowledge  in opening lines, many pit falls and black remains solid throughout. Both players can transpose into numerous lines.

Cons: White can chose from a series of openings, varying the stategic possiblilities, and usually transposes into numerous lines, thus requiring a bit of sound knowledge for both colors.

Suggestion: The Petrov/ Russian defense

1.e4 e5 2.Nf3 Nf6

Also, 2...Nf6 stops Ruy Lopez/Italian/Scotch, and can always transpose into three or four knights games, which is very drawish

Very aggressive for black. challenge center righ away, fast development.

1...Nf6 is my favourite - Alekhine Defence.

Pro: Gives aggressive, exciting games. Opponents are also not as well prepared for it.
Con: Can be difficult to play, and small errors lead to cramped games.

I dont play defenses. I play counterattacks. 

This is sound advice. I played the Caro-Kann (or French) for my first chess tournaments too. Just, as roi says, remember your opening principles and you should do okay.

My personal favorite is the Scandinavian- E4- D5

It really throws off some E4 players because it breaks so many opening rules- "don't bring your Q out early, don't move a piece twice in the opening, etc." It often inspires overconfidence which can be fatal.

Drawback- it's hard to get more than a draw if White really knows the best lines.

I just love it when my opponent plays ...d5, my play comes so easily

1...d6 that e4 patzer, then go all Hedgehog or Hippo or Pterodactyl on his butt. Not kidding.

Best openings for me
1.SIcilian Defense-(I play the dragon.)Tips the the balance right from the start.The idea is to create chances from a tactical perspective.
Pros-good middlegame counterattacking chances                                                               generally good endgame chances for black due to the extra pawn center
Cons-Lots of theory and some positional and theoretical nuances.(e.g.Maroczy bind).You have to dig the others yourself.

2.e5-Most principled reply to e4

pros-very versatile,rich with tactical and positional themes

cons-Lots of theory especially if you want to seek advantage rather than being content with a draw.For example in the King's gambit.you could grab the bull by the horns by holding to the pawn and following a theoretical line to "refute" it.Or you could use a low maintainance reply against it and hope that you are better accustomed to the positions that will arise than your opponent.

3.French Defense-

Pros-Versatile .It starts as solid but can explode into a tactical melee later on depending on how you play it

Cons-the age old Light squared bishop dillema.

4.Caro Kann-"Black is not White"

Pros-Solid structure resulting generally in superior endgames

Cons-Too solid

I've been trying out Owens Defence which is  1. e4 b6 then usually 2. d4 Bb7, 3. d5 e6

Pro: uncommon open and thus forces opponent to think for themselves

Con: White can occupy centre with pawns and gain spatial advantage

Not bad in speed or blitz. 

play opening that is comfortable for ypu.. thats all

I was a long time player of the Sveshnikov but recently switched to the French:

positives:
- Very diverse, can be very sharp, or drawish

-The best drawing weapon there is. (I play the Fort Knox against both classical and tarrasch, then theres the exchange. Their only real option for winning chances is the advance, also the only one i need to prep for).

- Nice endgame positions from many variations

Negatives:  

-c8 bishop can be awkward

-KIA is slightly annoying 

I can second this, it is my main defense to 1.e4.
I especially like the 'Bring down the table attack', 'Banned for life' variation. 

I would definitely go for the Petrov's defense... it is remarkably solid and offers alomost equal chances.