Let's take a survey of the best (most popular) way to handle the "Grob."  Post your opinion on the best choice for Black...

(1) Respond to White's 1. g4 with 1....d5

(2) Respond to White's 1. g4 with 1....e5

My vote is for response #2.

Go ahead.  Let's vote!!! 

Might as well respond with option 2. Making threats while moving is always good... unless the moves lose.

1. g4 d6

2.   i like e5 because i feel like i'm playing "white" now with that g4 pawn just floating out there doing nothing

I like 1...e5.

 

I've had the Grob played against me a couple of times here now, for obvious reasons I think, and I've played e5 once and d5 the other.  Granted I lost both games.... 

I play many times the Grop or also kown as Spike opening.g4-e5 Bg2-d5 a3-Bxg4 c4-pxp Bxb7 There are many variations,most players do not know this opening,and make eazy mistakes.I have won with this opening from playes 200-300 elo points  higher than me.

I do e5 feeling that white's kingside weakness merits a kingside attack.  And usually proceed with a sort of c6, d5 pawn structure, not necessarily in that order.

Hello "blanker."  I do believe that you got off cheap with the game you showed.  What I like about the 1....e5 variation is this: 1. g4 e5 2. Bg2 h5!? 3. gxh5 (if 3. h3? hxg4 4. hxg4 Rxh1 5. Bxh1 Qh4 6. Bf3 e4! and Black has all the fun!) 3 ....Qg5 4. Bf3 Qh4!? (yes, this moves the Q a second time, but it is a difficult move to meet because it threatens ...e4!) 5. Nc3!? Nf6 6. e4 Bc5 and again it is Black who has all the fun!

Enjoy... 

i like the d5 setting up a backward stonewall with black in control the setup allows the pawn to hang out there with out entering the center of the board.

Grob players want to see d5.  Give them e5 and most of their traps are left in the dust.