Small kids (between 8-16 yrs ) then Nintendo Wii, if kids are older then its best to let them select but they would probably want either of Sony Playstation3 +Move or Microsoft XBOX + Kinect
If you are buying Wii, i would suggest to get it offline with the hack that lets game backups & homebrew apps work. In mumbai you can get these at Alfa with hardly Rs 500 or so additional cost. Else you can do it yourself but it'll take up a few days of your time i guess.
Then you can download all games from TBP and put on a HDD and no more kids pestering you for games frequently. Games cost 2-3K otherwise. I only bought 3 games initially and then downloaded 20 games on to a HDD.
With hindsight though, I would suggest not telling your kids that you have all games downloaded or can download for free. everytime they ask you can download or enable 1 game ! Otherwise, having all Wii games just reduces its value for them and they lose interest !
Wii doesn't have realistic graphics like Sony PS3 Move or MS Xbox Kinnect etc but somehow kids love Wii more as the games are more interesting.
If you like shooting or racing games with realistic graphics then PS3/Xbox are better. Wii shooting/racing games will have funny characters and magical things going around !
Wii will cost around Rs 15K, if you want a cheaper console then PS2 for around 5K is good.
Regarding the best deals for any of these Consoles - I think the other deal experts will enlighten you. I was only commenting about the choice of consoles.