Re: Lahore vs. Karachi
Well Faisal and some others have put it very nicely. Karachi could have become the Hongkong or Singapore with the fast pace it started out soon after the birth of Pakistan but unfortunately the ethnic and other fights, alarming crime rate hampered the advancement of that city, which is such a shame 
Karachi could have been the true fort of Pakistan.
No one is bad mouthing anyone (except a couple of ppl). People prefer their own language (mother tongue), culture they grew up in, their food etc, which is very natural. Majority people who have expressed opinions so far, are Punjabi, if I’m not mistaken.
I personally turned down an Urdu speaking rishta but that was because I felt I would be speaking a diff. language than my own i.e. Punjabi for the rest of my life, (maybe cuz it was an arranged one). Even though we speak Urdu to majority of the people we meet, I am too much of a Punjaban 
But if the two ppl love each other than the rest should not make it an issue (Larki-Larka Razi to kia karay ga Qazi 
)
Karachi and Lahore both are the creme of Pakistan when it comes to fashion and marketing, and together they put Islamabad down (my poor Islamabad )
Suraj hai Sarhad ki zameen
to Chaand Baluchistan hai,
Dharkan hai Punjab agar,
Dil apna Mehran hai
Mein bhi Pakistan hoon,
tu bhi Pakistan hai 