Which indian defence to chose against d4 and why?

I know that i have 2 options:

1. i need a combo: 1 opening for d4, c4, Nf3 and 1 for d4,c4,Nc3. I was thinking about OID+Grunfeld or QID+Nimzo

2. transposition in 1 indian opening

I play the nimzo with b6 and Bb7.

There is a little trap with it as well.

If you are interested, search me some times at live chess, and in a long friendly game I can show you quite a few options. Or drop me a note. I can show you Nimzo Indian, Blumenfeld Countergambit, Benkő Gambit, Modern Benoni, Czech Benoni, and theese can make a compherensive repertoire for you as well.

The Grunfeld can still be played against 1. d4 Nf6 2. c4 g6 3. Nf3.  Just play Bg7 and after Nc3, play d5.  White can't play e4 without playing Nc3 first, at which point you play d5.  (Or you can play 1. d4 Nf6 2. c4 g6 3. Nf3 d5 4. cxd5 Nxd5 5. e4 Nb6, but I don't like this as much).

Anyway, I used to play the Nimzo-Indian / Queen's Indian combination (for when white plays 3. Nf3 instead of 3. Nc3), but have recently been experimenting with the Grunfeld. So far I'm liking the more open, tactical games the Grunfeld seems to lead to.  I prefer the Grunfeld's general plan of immediately trying to eliminate white's center rather than the NI/QI's plan of trying to restrain it, though I recognize that this is probably simply a sign that I don't understand the NI/QI openings well enough to play them well. :\

I don't know much about the actual theory in Nimzo-Indian, but you can put a lot of pressure on white and his c3-knight with Qa5 and Ne4 if white isn't careful and doesn't castle right away. That's probably not a very useful information... I have more experience with white pieces - white usually puts pressure on h7 pawn and wants to take control over the c-file, black has a little problem with developing the light-squared bishop because of e6 pawn and blocked center by d5 pawn (a8-h1 diagonal). These are probably some of the things you should be aware of.

It's mostly about style of play with classical openings - I feel quite uneasy when playing Grűnfeld, but I'm comfortable with Nimzo. I think the best way to see what suits you the most, is to play both openings and to do a little research beforehand (there is some theory even on wikipedia). After some time you get a feeling about the opening even without learning theory behind certain moves.

Vso srečo!

Can you tell me a secret?