What is black's best defence against Nf3?

Love starting out with Nf3 as white, but have never played against Nf3 as black... 

1. Nf3 is an attempt to develop, control some central squares and keep Black guessing. It can often transpose into the English, Queen's Gambit, King's Indian or other systems. The problem is, you won't know what it has turned into until it turned into it.

For instance, if you play 1...d5, you could end up in a Queen's Gambit or London System or Colle. Or you could end up in a Reti if White plays 2. c4

1...Nf6 is no guarantee of a smooth ride either. When I used to play this stuff, games often went: 1. Nf3 Nf6 2. g3 g6 3. b4

1.Nf3 c5 allows the option of going into the symmetrical English with 2.c4, or transposing into the Sicilian with 2.e4.

Ah, but if you don't like to play those things as Black, then you're still .

The thing that stinks is that there are so many transpositions.

And that is the attraction of playing Nf3

I always answer with d5 and try to transpose into Qgd or slav :)

I like ...f5 also, but you must be ready for 2. d3 with e4 in the horizon.  Otherwise, you typically enter into standard Dutch lines.

I play 1....d6.

As long as d6 is main defence against 1.e4, and 1.d4, don't see any problems playing it against 1.Nf3. Chould be wrong though, because d6 isn't really my thing.