People started refuting the comments to the original poster and dragged themselves into the same South Vs North discussion.
I dont know how people compare such things. North have plenty of states in comparison to South. If I take Language based differentiation then Tamil originated states are 4 and while Devnagari based plenty of others. This south vs North division was too much before 2000 but after IT boom everything got changed.
Due to evolution of Infosys and other org, North Indian people started migrating to Bangalore and Chennai while for the same monitoring and high positions South Indians later moved to North India. Now population of North > Population of South. So Changes looks more obvious for N Indians.
In Delhi, RK Puram & Munirka area is full of S Indians and Noida is another area due to HCL. I have been to bangalore, Mumbai and Currently in Delhi, I found the best cosmopolitan city is Mumbai. Reason is it is having, Gujratis, Bhaiyyas (us), Parsis, Marathi, Malyalis (they love to go to Mumbai in comparison to Chennai, dont know why?), Telugus and then Tamilians. I never found such a large variation in any other city. Another point is, except Shiv Sena, Attitude in mumbai is truly cosmopolitan.