As if the title of second city can be decided by a poll. The monkeys must be mistaking this country for a democracy. As people have mentioned since, our city is not great at promoting itself so here are some aspects of Birmingham to be proud of.
1) The Lord of the Rings. The three books (along with the Hobbit) that created the whole fantasy genre were written by a Birmingham author, JRR Tolkien, inspired by Moseley Bog.
2) Black Sabbath. I am fed-up of listening about how influential bands from Manchester are (in any case, sporting and musical achievement is greater in Liverpool). They only dominated in this country for a small section of the 90's. Black Sabbath are one of the most influential bands in the world with Tony Iommi credited with inventing the heavy metal riff. And can you imagine an MTV show called "the Gallaghers"?
3) The Mini. This characterful car was first developed and built in Birmingham in 1959 until production ended in 2000? The new Mini was developed in Birmingham but is now built in Cowley by BMW.
4) The Lunar Society. In one of his books on the history of industrial Britain, Adam Hart-Davis devotes an entire chapter to Birmingham in which he states you cannot write a proper history of Britain without mentioning Birmingham and in particular the work of the Lunar Society.
5) Modern architecture. Birmingham may not have the tallest skyscrapers (in fact I believe we cannot because of the nature of the soil round these parts) but that has not stopped us creating some of the most recognisable buildings in the country. The Rotunda is being redeveloped, while the new Selfridges building may be controversial, but at least it is different.
The fantasy genre. Heavy metal-riffing. One of the most (if not the most) iconic cars in the world. Power when Britain was emerging into a superpower. Modern Landmarks. Birmingham's greatness transcends the city.
Tell you friends how great Birmingham, England is.