I think Rob is right. It is not all about weight. You should consider the ride and build quality. I think the weight differentials you are talking about are pretty small, think about it, it is probably a lot cheaper for you to lose half a kilo off your paunch Ajay, you will save money on food and on the bike.
I have to admit though that I have absolutely no idea where I would even start. I would not discount De Rosa though as they do have some damn beautiful bikes.
You should go to Dauphines and speak with them, they have the blingest bikes in town and they will advise you on what type of bike is best for your build etc.
Cheers
Marek...