Back in the day it would have been Nintendo easily, yet now on the PS3 I'm seeing more first party exclusives than the PS2 and PS1 had. Don't worry, the majority of their first party exclusives are great. It's only SOCOM4 you should be wary of.

I'd say it's purely a matter of taste between Nintendo and Sony, I don't think there's any real argument that could put Microsoft in the mix, Sony and Nintendo have the lions share of exclusive IP (And I mean exclusive, not just exclusive to their platforms...ergo, on PC doesn't count).

I personally prefer Sony's exclusives, however, I could quite easily understand someone going with Nintendo for Mario/Metroid/Zelda etc...

At least for me it's Nintendo by a far margin.

Nintendo do a lot of exclusives and most of them are great and they have a appeal for everyone, i can't show games from my PS3 for my girlfriend, but sure she always ask me to play Mario Kart Wii, Wiifit+ or Wii Sports (Resort)... and that's is a great point over Sony.

Sony that has several good exclusive games, but they appeal for the same age gap everytime and the ones that don't... i didn't like them (For example i didn't like Little Big Planet at all).

And Microsoft have few exclusives i like, but the few of them are impresive GoW, Halo and Fable i'm talking to you! (not interested at all in Kinectsomething games or Dance Central)

Nintendo>>>>Sony > Microsoft

Any answer that isn't Nintendo is automatically incorrect.

Nintendo, Sony, then Xbox360.
Its not even about the replay value because I'd still play halo 2 online if they still had servers for it.
Nintendo does have those old franchises they update so often- that's nice and expected (and guaranteed with the system)
The new IP they have or the ones they revive are usually underrated or ignored. They got it but if something else sells better then its the customers to blame.

There are IP that simply underperformed, like Red steel, but if you want generation defining games then its the Wii series that defines the Wii. Wiisports blew up stores like it was nobodies business- without that title the Wii wouldn't have moved as many systems. Since then the producers have been fumbling with that franchise til it got the way it was.

There was another franchise that was new to the Wii exclusively - the bit trip series.
Tatsunoko versus capcom.
Conduit, that other sega game, and no more heroes were all (once) a system exclusive. No more heroes outshone the rest and went on to the psMove.

If Nintendo came up with new IP's to fit even more genres, it would make the situation even worse for third parties on their console. It's already bad enough as it is. For example if NIntendo makes a serious Top Gear rally game for WiiU , all other rally games released after that SUCKS!

BTW the Super Mario 3d X is kinda a new IP for Nintendo. So there are like 3 branches of Mario right now: 2d Mario, 2d/3d Mario and 3d/3d Mario.

The Super Mario 3d brand is playing an important role for the game industry right now: It shuts up the "3d is useless in games" crowd. Seriously, the internet has more or less  shut up about it. This is how conversations usually go on internet forums after SM3dLand released:

X: 3d is cool!

Y: 3d is useless.

X have u played  SM3dLand yet?

Y: No

X Then Shut the F*CK UP!

Y: Sorry

Well nobody buys a Ninty console for the 3rd party selection, so that right there pretty much says it all.

Next would be Sony, who have really built up their 1st and 2nd party exclusives this gen but lost alot of the 3rd party exclusive titles that made PS2 the console to own last gen if you wanted something other than Nintendo games or Halo.

Sony has the best exclusives. Great variety and quality. That's all I will say. Not gonna get heated up over this topic again.

Rol, I remember a time when 3rd party games used to sell side by side with Nintendo 1st party games, were as successful if not more successful than 1st party Nintendo games at times. Do some of us even realise that Street Fighter II on SNES sold 6m copies and is still the best selling Street Fighter, nay the best-selling capcom game of all time? http://www.capcom.co.jp/ir/english/business/million.html

Then there were Mega Mans 1 to 6, Final Fantasy, 3 Castlevanias, 3 Ninja Gaidens, all excellent games with solid sales.

My times have changed if 3rd parties can't keep up with Nintendo... The only exception at the moment seems to be Capcom with MH 3G and RE:R.

i would say in terms and quality and quantity:
Sony>> Nintendo>>>>>> Microsoft

in terms of my tastes and quality:
Sony>> Microsoft >>>>>>>>>>>>>>>> Nintendo