Advice for buying laptop

Hi guys,
So I'll go straight with the topic. X’mas is coming, and I'm thinking to get a laptop for my boys, they always complain about the aged laptops in my house! I'm tired of them nagging at me so I decided to buy 2 laptops for them as Xmas surprises; I believe they'll crazy about it!
My colleagues told me that I can get some advices here, so here I am, any laptops you recommend

Please fill the following before asking any query in this section of forum.

1) What is your budget? (INR or USD)

2) What size & weight consideration (if any) would you prefer?

Netbook; 11" - 10” screen or less
Thin and Light; 12" - 14" screen
Mainstream; 15" - 16" screen
Desktop Replacement; 17"+ screen

3) What are the primary tasks you will be performing with this notebook?

5) Any typical configuration in your mind you're eying for ?

4) Are there any brands that you prefer or any you really don't like?
a. Like:
b. Dislike:

6) Anything else you would like to say?

Screen resolution ( 768p (HD) / 900p / 1080p (Full HD) )
Battery back up ( normal (3-4hrs) / extended (5-7hrs) )
Purchase place ( Online (eg - flipkart, infibeam) / Local / Abroad (do mention the country) )