d4 d5 vs. d4 Nf6

Hello all,

Up to now, I almost always invariably play 1... d5 versus d4. Most of the time I get a QGD (1. d4 d5 2. c4 e6 3. Nc3 Nf6)

I was thinking of playing 1... Nf6 2.c4 e6 3. Nc3 d5, transposing to the same thing, but inherently with this move order, there are nuances. For example, if you play d5, you're not going to play a Benoni or a Benko Gambit. Nf6 leaves the choices open: Grunfeld, Benoni, QGD, etc.

Are there anythings that are no longer available through an early Nf6? Also, what theory do I need to know if I cannot transpose into a QGD?

Thank you.

well Nf6 prevents you from going into a dutch as it blocks your f pawn, but Nf6 is definitely more flexible and probably better. another flexible move is 1.. e6 as long as you're comfortable with the french if they play 2. e4. e6 allows a QGD, a benoni, a dutch, a keres, queens indian, or nimzo indian, but doesn't allow a grunfeld. I personally play Nf6 though.

After 1... Nf6, what are some common white 2nd move responses?

in order of popularity: c4, Nf3, Bg5

a lot of lines that go all over the place from there.

after c4 i play e6. if Nc3, then Bb4 (nimzo indian) if Nf3 i play c5 and get a benoni where the f pawn has been blocked by the Knight on f3 preventing the dangerous f4 lines.

after Nf3 i play e6 and it usually turns into a QGD from there

after Bg5 (which i've only seen a few times) Ne4 attacking the bishop with c5 to follow

One disadvantage of playing this move-order is that it allows the Catalan (1.d4 Nf6 2.c4 e6 3.Nf3 d5 4.g3) but it seems you allow that anyway with your move-order. I like 1...d5 for a number of reasons, not least of which being that I can meet 2.e3 with 2...Bf5, that 2.Bg5 is basically useless, and that I play the Semi-Slav via a 1.d4 d5 2.c4 c6 move-order and would very much like to see everyone play the Exchange variation (at least below IM level). 

Apart from that, there's nothing really wrong with it. I played that way for a long time to get the chance to play the Nimzo-Indian. I don't actually recommend playing 3...Nf6 after 1.d4 d5 2.c4 e6 3.Nc3 though as it allows the Exchange Variation of the QGD, which is considered to be very risky for Black these days. Most top GMs prefer 3...Be7 there where 4.cxd5 cxd5 5.Bg5 would lose a piece, while after 3...Nf6 it is the main line. So instead White puts the Bishop on f4, where it has its trumps but this is generally not considered to be as dangerous as allowing Bg5 without White playing Nf3 (because the e3-Nge2 plans are now available)