For myself, the stress on the first syllable is much more natural, although I think in the media they usually pronounce it with a stress on the second syllable. Such pronunciation colored as "rural" to me even though it is used more often in the media.
I think in Moscow and Moscow region stressing the first syllable is more widespread.
Here one can see a video the speaker pronounces the word with stress on the first syllable:
http://www.youtube.com/watch?v=U-xCOsbSBe4
http://www.youtube.com/watch?v=TYzb7fM2v_E
Here the speaker stresses the second syllable:
http://www.youtube.com/watch?v=krnF4WeeS0A
Here the speaker starts with stressing the first syllable but then switches to the second (apparently in attempt to be more "correct"):
http://www.youtube.com/watch?v=5RSvVa0jNCs
I think stressing the first syllable sounds more natural and easy to pronounce, but stressing the second is more grammatical formally (or perceived by the people to be more grammatical, as with the word кофе being masculine gender even if more natural to consider it neuter).