I will offer you my own perspective on this matter and I hope it helps you decide what is best for you.
I was personally, not very good in school. I was average - good in some subjects, weak in others. Generally I'd score in 70s-80s range (pathetic by today's standards but average then). I did, however, hold an interest in engineering and technology. I'd tinker around with practical apparatus in the chemistry lab every day. I'd try to understand reaction mechanisms and colouration caused by various reagents. I'd try to see the kinetics, etc. I used to debug code in my spare time - I was a computer whiz once, deeply interested in software as well as hardware. I used to top the computer science subjects at school, which sadly had only a grade and were never part of the total marks in the report card.
When it came down to it, all of my interests were discouraged by immediate society in favour of studying harder to get more marks in 10th, 12th and then the entrances. But I never prepared seriously, thinking that I must clear an exam of my own volition and not by being "coached" for it.
I suffered very badly for it. I was interested in only two branches: Computer Science/Engineering and Chemical Engineering due to my childhood tinkering in both those fields. Due to my entrance marks, I forgot about IIT, NIT and BITS or even my two favourite branches: They were all out of reach. I could not even get BSc in Computer Science with my 12th score. I ended up studying a branch that I was only partially keen on in a 3rd tier college in the city. Nearly all my dreams, all my interest was killed in that one year of 12th. I was not keen on dropping, because I had never attended coaching in my life and I was not prepared to start now. I took the ball that was given to me (and later, I would find out that most people, including the toppers, also took the best available option rather than what they really desired).
The kicker was that my interest was never related to a desire for a job. I wished to study because I had an interest. But, with the Indian education system, that does not take into account any practical skills or even a statement of purpose, I had been ditched. Over the years, I accepted the situation. The college taught as well as it could with its extremely limited resources. But basically I did self study. I passed, somehow with decent marks. In terms of practice I was/am decent with my branch of specialization today. Over time, I did manage to try and link myself with other branches by means of magazines and self study of textbooks from other branches. It took a lot of time, and money.
But the aspirations for getting a job of my fellow friend engineers took away my desire and interest to study what I really wanted and made my life ten times more difficult for it. Can I blame them? No. But even for postgraduation, a similar situation prevails. You have an easier option in the US, where you can pick and choose majors (or minor if you could not get your desired major) and can always choose electives to suit your own interests. This is just not there in India.
The earlier posters are right: Indian education system is not designed for people who wish to study and/or research. It is intended, meant and deliberately favours those who have a "I need to get job" mentality. If you fall into this crowd, I suggest you stick to India. If not, go the USA way. Don't get me wrong, Indian education system is not bad at all, it does have a decent quality to it, but you need to understand who it is meant for. You can be like me and still be successful, it just takes much more effort in India than in the USA.
I hope this gives you a better perspective on the matters. The USA probably has it's own cons as well. Nothing is inherently good or bad as such, it just depends on what suits you and what doesn't. No one can objectively judge intelligence by the means of any one test, that is why the USA has a holistic approach to admissions.
!!!! hell, now what ? 
