I had this discussion last night leaving the stadium. We both thought the atmosphere last night was excellent, even before we scored but especially so once we'd equalised.
One thing we also spoke about was this "Maine Road Atmosphere" myth. Sure, Maine Road was great and when the old standing Kippax was in full voice it was amazing, but you can't tell me that our stadium now isn't better than the latter years of Maine Road. It might take a bit to really get it going, but that's because it's bigger by 15000 or so. Also, since we moved, we've not really had a great deal on the pitch to make it fulfill it's potential. With games like Lisbon second half and last night, I think it proved that if the team perform and the fans also do their bit, the Etihad is far far better than Maine Road ever was.