Well, according to me,metallurgy is not a branch worth taking.Chemical is not a bad branch for placements,but guwahati is the least preferred amongst the older IITs........The best place to do electrical is NIT warangal{xcellent faculty}.but dats not an IIT{althought almost equal to IIT} My choice:

NIT warangal~IIT guwahati>NIT trichy>>>>>>>>>>>>>>>>>>>>IIT Kanpur

Dear Jack,

if there is no as such interest in particular branch then metallugical @IIT Kanpur wud be the best option for you ..As IIT K is one top three collages in India. Also the future in metaallrgy is great in terms of High end organizations Like BHEL, GAIL, ISRO , DRDO, BARC, and many other like SAIL, Jindal steels , Bhushan Steels .. 

but there are not much requirements as comapare to other like electricals etc ..  People from metallurgy prefer to got into research and pursue M Tech.  If done from IIT chances of going out of india are also worth as outside inida like in germany , ukraine, france, russia ppl are recruiting metallurgy students..

At last i wud like say clear ur mind and think of what u love best. dont compromise on that coz u got to live with it all ur life..

All the best for your Future !!