Very difficult to know. I've actually been sad enough to spend time reading gamespot.com pretty additively just to keep myself up to date on them all, so i at least know the one I've chosen isn't going to flop terribly and my money isn't going to waste.
It's an investment at this point, you're buying it because of what it's going to provide you in the future, predicting that far ahead can be difficult.
I'd say the wii will be the most popular to start with, for sure. There's like 16 wiis to every one ps3 it's going to outsell the ps3 easily.
Beyond that is any ones guess, the ps3 uses blu-ray if that flops (which I'm hoping it will) the ps3 is going to flop, imo.
The xbox360 is using HD or whatever, that's like a cheaper version of blu-ray but has less memory, hopefully that one will be the success which would pretty much nock the ps3 out.
Leaving the 360 and the wii. Whichever way that goes is anybodies guess, it comes down to what people want.
Do they want a console with superb multilayer that costs a lot and is just the same old thing?
Or do they want a cheaper, new and different console?
There is A LOT of wrong and stupid rumors going around about the wii, from idiots that've taken one look at it and went "OMG THAT MEANS YOU HAVE TO SWING YOUR ARMS AROUND LIKE AN COMPLETE IDIOT".
"NINTENDO HAS KIDDIE GAMES"
Yeah, stupid crap.
As for the rest of it, Nintendo is cheapest to make games for..it's also the one console that's going to let developers be more creative because of the motion, 360 follows and the ps3 is final being the most expensive and hardest to produce for.
Because of that, i'm guessing the wii will have a lot more games made for it than the cube, with any luck (which, looking at the line up, it will do..it's already getting ports from the 360 and ps3, adapted to be better and take control of the wii remote.)
Either way, Microsoft have a bottomless money pit, they can give the consoles away if they wanted, so you have no worries about getting a 360, it's a safe bet.
Nintendo have all sorts going on that give them income, their also gaining money on the console (unlike the other two) so they certainly are in this for the long run and wont drop the wii, that's another safe bet, imo.
Now as for Sony (i know this seems extremely anti-Sony, but I'm just reporting back on everything i know cause I'm sad and need to get this info out.), they have A LOT riding on the ps3, they've not been doing to good lately, if the ps3 flops i can't see them holding out. Their slowly losing there hold on all the good games, the 360 is gaining them thanks to MS bottomless money pit.
Only thing i see worth playing on the ps3 is mgs and even that, really isn't impressive. Graphics for there games all look about as good as the 360s, certainly not worth the 600 dollar price tag.
Anywho, if blu-ray picks up and gets popular, Sony will win but will further lose it's dominance over the market and will lose it the next time round.
Wii will gain More games, get more of a grip on the market but still be in third unless the blu-ray flops, then they'll move up to second place - however will, over time gain back the market.
360 will take Sony's spot in time, they've already begun taking over..it's just a matter of time, they will be second this time round or first if the blu-ray flops.
I'm so sad for writing all this and knowing it all.
)
and i mentioned something about the "kiddie games too"...but yeah...its what you expect from PS3 fans 
And as for the graphics being the same as the 360, they WONT. The relase games for the PS3 will have the same graphics as current 360 games and they have had 1 year to figure out how to make good games graphcially using the systems strengths. This time next year, the PS3 games will have way better graphics than the current ones now.
