Which is the best defense against the Queen Pawn Opening?

I usually use 1 ...g6 , is it a good move?

b5 or d6

b6 or g6 is also a good move but using d6 will be always better because it is a significant move which covers up the e5--c5 position giving us an opportunity to occupy the central territory. Usually grandmasters go for d6 or e6 due to the same reason you can even form a silician defense from it.

but.. after e6 white plays dxe6, and you lose one pawn...

I like the semi-slav.

What do you do after g6?

One move isn't an opening.

That looks OK to me...though the e3  pawn may also end up on e4.

If that isn't working out for you, the problem isn't the opening system chosen but probably tactical mistakes or positional errors that lead to King-side attacks.

It looks like the pirc defense...

I like the albin countergambit or the benoni. But I play the semi-slav occasionally too.

After g6 comes Bg7 , Nf6 and then O-O

I think Siegbert Tarrasch refuted 1. d4 some years ago.

As a d4 player, I usually don't like it when my opponent plays an early ...c5.  The reason is that I like a slow, quiet, positional game and ...c5 often forces me into a sharper game.  It's not necessarily the best plan for Black, but it has a psychological advantage when used against me!

if you are playing black it looks like you already have an opening the kings indian defense but i think you should change your move order

The best defense is a sharp mind, strong abs, and lungs of glass

then you play 2...Qh4

for what it's worth, I used to use the ...g7 move to bring the game into Alapin (or Smith Morra) Sicilian, and it worked for a long while,

...and I was happy enough...

But then one day, folks stopped liking getting dragged into a King Pawn game when they started a Queen Pawn, and it was like overnight everyone I played that variation with...changed to I don't know. Grunfeld, or Pirc.

Needless to say, it was not my cup of tea (I always have liked coffee) and I have continued to try the King's Indian against the QP games by leading with  (after 1. d4) ...Nf6 2. c4 g7...

However, researching other players who Kings Indian against the QP is a test in itself. John Nunn uses it, and loves it. Kasparov used it a lot.

But they are Nunn and Kasparov, both with huge opening books to their credit, while I am mr. boneman, lowly Chess amateur bumbling my way through it all.

Against 1d4, the Kings Indian has always given me the most trouble. Seems like black gets all the attacking fun. I think qgd and Slav are the most solid. 1750 uscf. 

This topic has come up a number of times since this thread first appeared in 2013.

I've had good success with the Slav Defense, where ...d5 and ...c6 allows Black to play his c8-Bishop out, usually to f5 or g4. In many Q-Pawn games, that Bad Bishop becomes trapped behind his own Pawns.

In my Op I love 1e6. Transposing to some of my favourite positions that I’m in the middle of studying especially including the English defence