I found myself in a game with this position. Last Black's move was a Queenside castle, which let him a little bit uncovered. My first spontaneous move idea (which I finally played, because of time trouble and having no really other interesting idea) was to play Rc1, to put pressure on the king on the C column added to the fact that my bishop on f4 makes the move Kb8 impossible (and then c4 etc).
However, this can be easily countered just by playing Bd6.
So, we all know the importance of a threat (which is, like Nimzowistch said, stronger than the execution), but do you think it's a good move in this position ? or, knowing that it can be countered, do I had to choose another "more effective" move ? (like I don't know : a4 ?)
Would you have played Rc1 ? If not, what would have been the best move ?