Decent Budget phone

go for desire 820! if camera is your main concern! it has the best camera in this range (Personal Experience)

Go fro S 4. I myself have s4. Am happy with performance of s4. Many feature.

Check out new mobiles launched by HTC like 820 series and 826. Go for lumia 830 only if you can get it for 20k. If camera is ur priority, lumia 1020(22k), lumia 925(18k in poorvika) is the best choice.

I think HTC Desire 820 would be good for u...It has a decent camera(13MP), Octa core processor, 16GB inbuilt memory, 2GB RAM
And since it's a good brand as all know it will surely last for years
Also it's of about RS.21,990

if you are looking to lasts for about 2 years as well as not lag, I would recommend you to try a windows phone(lumia 830), it doesn't lag, has a great camera, though u need to increase your budget by 1K and also there will be lesser apps as compared to ios and android but the store is getting better day by day though hopefully u'll love it

As far as oneplus one is concerned the availability is a concern plus it has been taken off the shelves in india for sometime
Moto x I have heard has a quite fragile screen?
Is it true??

One plus One is the best phone under your category...but in ur choices Moto X is a winner...and is available around 17K.