I listen near-field, simply because I have no other option, and also because it suits the presentation of my speakers (large Tannoy DCs), and how they interact with the room I use them in - and indeed most rooms, due to their inherent design.
Also, generally but not always, I prefer the sense of 'intimacy' and immediacy one gets with near-field listening, but conversely, I can enjoy the 'walk around sound' effect ones gets with far-field listening, in a large room, as long as the acoustics are good.
One also has to consider that the longer you allow bass waves to develop (by sitting further away from the speakers), the more bass you can hear, which can swamp the sound and make for a rather 'phat and plummy' sonic presentation, which I detest. In that respect, give me the faster and more immediate near-field listening experience, any day!
In terms of the 'big room vs. small room' thing, for me I'd rather have a GOOD room (acoustically), than big or small, so as usual it's QUALITY, not quantity, that counts!!
Marco.