What are the considerations before buying a Full Suspension bike (India)?
There are a few questions to ask yourself. 90% of the time what sort of riding are you doing? Hike-a-bike where you'll repeatedly walk your bike up a hill and ride down, do you commute by bicycle, etc. If you want to use it solely for riding down hills and hucking off jumps and nothing else then maybe get a downhill rig. If you do any other form of riding at all don't get a downhill specific design. Their made to be ski lifted up mountains and then ridden down, that's about it.

From what i read though it sounds like an all mountain or all around trail bike would be ideal for you, something you can use the lockout's on the suspension to get around. Trying to ride up large steep hills on a downhill bike is pretty horrible and tiresome. You also loose a lot of work in the bob of the suspension if you're just tooling around town. 

A good quality trail bike with 120-140mm suspension with lockout sounds like it would be right up your alley as far as the type of riding you're doing. The most important part of the suspension system is your body after all. But with 120-140mm of suspension that should be plenty to soak up what your doing but still be usable in other aspects and styles of riding as well.