All the subjects are good at Delhi University and depending upon your interest,you can choose one of them. If going to popularity,number of students enrolled and jobs opportunities,some best course are-
1- Bcom
2- Economics
3-Political Science
4-History
5-English
6-Chemistry/maths/physics
7-Geology( As I am currently enrolled in it and I know a lot about career in geo)
You can ask me about any subject if being in doubt