North Indian food is very similar to Pakistani cuisine in that it often includes kebabs and other grilled meats. There is a high propensity to also use dairy products in the cooking. 

Famous foods that are typical in north India include: 

Tandoori lamb or goat 
Rotis and parathis 

 West India West India is dominated by goan food, this includes fish and coconut curries, there is also a gurjurati influence in the region. Both are generally sweet curries. 

 East India
Food in east India is quite alien from what I'm used to, it mostly consists of lentils and fish, it's quite basic but does share influences from bangladeshi cuisine 
 South India
Hyderabadi cuisine is largely rice dominated for obvious reasons, here you get your biryanis and kerala food. 

I don't really know too much about street food, but i hear that there are interesting regional variations there - and some tasty foods!