So, I went to some dealers and found some solutions.
Remeasured the room, it is actually smaller than I thought, around 6mx6m, 3.30/3.50 high.
As for the TV, my choice would be Panasonic TX-P50GT30.
I don't give a damn about the 3D stuff, but 1350 euros seems ok to me. Cannot use bigger TVs as the size limit is 123cm in lenght... I could alternatively find something around 156 cm, but that becomes quite expensive (3300 euros for Panasonic TX-P65VT30E)
For the speakers I am quite convinced about Indiana Line.
The idea is to have two floor standing loudspeakers (Tesi 542), one centre channel loudspeakers (Tesi 742) and 2 closed box speakers to put at the back of the room (Luna, but unsure.. Tesi 242 might be better?). One of the key aspects of the choice has been against the size: can't be more than 16 cm wide, and this one is 135 mm.
Subwoofer: Indiana Line - Basso 830
Now what is probably the most crucial thing: the amp.
My choice could be a Denon AVR-1912.
But here I have a lot of questions and requirements:
First: It must be able to sustain all the speakers mentioned above and a subwoofer, PLUS two speakers in the kitchen. So, 5+2.
Question: will it be possible to - play what I see on the TV only in the main room, isolating the kitchen/making it silent? (i think it should...)
Second: would it be possible to play simultaneously two different things? Music in the kitchen AND TV program in the main room?
Or would it be possible to play on the Xbox, but have for example only the front speakers using the sound coming from the Xbox while all the other speakers play music?
Third: a) AirPlay. How does it work exactly? I kind of understood that it connects your iPhone wirelessly to the Denon, allowing you to "press Play" on the iPhone and hear the music in the whole room. Is it this way? Works also with photos? I mean, can I look at the photos I have on the iPhone and see them on the TV with AirPlay or in some way with Denon AVR-1912 or not? Or do I need to buy the wireless dock, ASD-51W?
b) It should work over the wireless network, right? But there is no Wireless/ADSL network in the house (and never will be, at least in the near future, because the house is meant to make me stay away from work and just relax). Does the Denon create its own wireless network without internet data or do I just miss all the functionality?
c) Would it be possible to wirelessly show pictures or play music that i have on a MacBook Pro on the TV? There is no Internet connection in the house, but by buying a router would it be possible to create just a network in order to allow the Denon to display what I want (movie or pictures) from a Mac or is this just pure Utopia and I would need to use a HDMI cable?
So the costs are:
TV - 1300 euros
Speakers + Subwoofer - 1100 euros
Amp - 500 euros
Total: 2900 euros.
The cables and the job I suppose would be around 300 euros, so total comes to around 3200.
I have some space to make improvements, around let's say 800 euros, which can be on an amp that allows me to do what I mentioned in the questions...
The dealers has also ONKYO and Yamaha products at a competitive price.
Any further help is appreciated, the things you told me came very useful so far!