Firstly congratulations. If you think your journey is over realize that your journey is just about tobegin. The answer lies with what you want to do in the future. Have you cleared JEE for a good settled life post IIT then you may opt forComputer Science. This DOES NOT mean that other departments will not fetch yougood job or that Computer Science will fetch you a good job. Everything lies within you. There are people who have opted for MSc. Physics with a single digit AIRbecause of interest in Physics. So I would say if you have no particular interest in any particular fieldchoose Computer ScienceElectrical Engineering preferably in IITB. Why IITB IITB is a place where academic load is considerably less and hence gives youtime to pursue any other interests of yours. Of course you can spend that timepursuing a project if you are interested. Decision is yours.