Sigh ! Lots of misinformation and half truths here.
@cybertechie - The Canon 550D is undoubtedly a good camera but it sells for around 37k at Letsbuy. I am not sure about the local market but even on ebay it around 37k. If the OP can afford it its a very good buy.
Buy Canon Best Selling DSLR EOS 550D (with EF S18-55mm IS Kit) at Best Price in India - Also find Specifications, Photos, Features & Reviews
@ vercetti - Please recheck. AFAIK the price is around 37k only. If you have some links please do share the same.
@jdutt - The 550D shares the same sensor and metering system but a higher end camera has a lot of other features which people pay a premium for like faster FPS, weather sealed body, better viewfinder, more dedicated buttons, faster AF, more customizable options, more responsive body, etc.
@bhupatib - Sirji, that site is not the best place to do any meaningful comparison. You will not be able to tell the difference in IQ at any sane ISO levels.
So IQ aside the Canon has better features like AF support for more lenses, a larger and more hi-res screen and better third party support.
The D3100 doesn't have a body AF motor and so wont AF with a lot of old lenses.
BTW, Canon bodies also don't have a body AF motor !
(Shows how accurate that site is !)
All Canon lenses have the motor in the lens while only some Nikon lenses have AF motors built in.
For your budget I suggest either the Canon 500D or the Nikon D3100. Do note that Nikon's 50mm lens costs 12k (the one with AF compared to the Canon version which costs only 5k).
Otherwise either camera system will serve you well.