To me, I think it all depends on the upcoming games and new hardware. (GEM and NATAL) The PS3's slim effect is starting to wear off but they still have momentum as the PS3 is still outselling the 360.....barely. If the games wins then Sony definetly will triumph but if the hardware wins then Microsoft will again have the advantage over both Sony and Nintendo.
We'll see.
Generation 8 Predictions so far.....(as of 9/2013)
Console that will sell most: Nintendo Wii U
Who will sell more consoles between Microsoft/SONY: SONY