Best sectors to buy a house in Gurgaon?

I am thinking to buy a house, Gurgaon is better or Greater Noida, I would like to know what are the best projects, companies and best sectors to buy a house in Gurgaon/Greater Noida, I have a budget of Rs.40 lakhs, please let me know, Property consultants/real estate firms are also welcome to give their advice and if I like their advice, i can buy through them also. thanks in advance.