Well, I do think system sellers will be thin on the ground for a while.

The Wii has passed the point of system sellers already I think - it has the motion control, it's currently the PS2 of this generation (saleswise) and it's just going to sell.

360 doesn't have any franchises left to debut (so far as I know) and its also reached the point, I think, where any new Halo, Gears, etc. will be mainly absorbed by the current install base - i.e. you'll see a modest spike in HW sales for the really big titles but nothing of the level of a true system seller. The two exceptions for 360 I think, are FFXIII and Natal. Each could drive systems, although I suspect Natal is more likely to help 360 than FFXIII.  Really, though, this isn't a negative for 360 I think, more proof that it doesn't rely on a single title to drive adoption anymore (Halo I'm looking at you) and has reached a big enough install base where system sellers are less likely to happen with sales more driven by price drops and the extent of the back catalogue.

The PS3 is probably in the better position, but that's overall a negative vs positive thing in my view. It has the smaller install base, it has the larger percentage of big franchises still to emerge fully (or at all) onto the system. GT5, FFXIII, GoWIII should all drive spikes and at least GT5 and FFXIII should be system sellers, even if only in Japan and Others. GoWIII may drive systems or just a more modest spike.  Really though the PS3 could have done with those titles, and the attendant boosts, earlier in its life, giving it a much larger install base and allowing it to move beyond the point if individual system sellers.  Still, better late than never.  I guess if  the rumours are true Sony might try and mix some of these big hitters with some price cuts to further increase they odds they will drive a lot of systems.  It's a catch 22 - Sony needs to not lose money, but it needs those titles to really boost sales and for the PS3 install base to increase with a big jump.

But personally, if I look at PS1 and PS2, I don't see their success being down to individual system sellers but broad acceptance and solid sales across a whole pile of genres. The Wii may be more of an exception than anything else this gen as looking at it overally vs the PS1/PS2 its success does seem more hinged on some key titles (Wii Sports, Wii Fit, Mario, etc) than having a broad set of strong sellers across lots of genres.

But then this gen is different I think, more split, less definitive in whose winning and losing, and why.

Well, we can be sure that "system selling games" exist in Japan, just look at what happened earlier this year.

As for the rest of the world, it depends on whether the game strikes a chord with the average consumer's interests.

Yes there is.
See the posts above mine

if it has Wii in the name it will sell systems

Zelda, Mario, Halo, Final Fantasy, Metal Gear Solid, GTA series are all system selling franchises.

The ONLY reason I went out and bought a Wii, was because I played Wii Sports

thats the reason

after that i got into other games, but that was my main reason originally

100 percent system seller game

halo 3 was the best system seller i saw makingg the 360 sell more than the wii in september. 360 sales more than doubled. i think halo reach is a system seller since its almost a remake oh halo CE

GTA. Gran Turismo. Mario. "Wii". Halo. Final Fantasy. Metal Gear Solid.

Probably many more.

gears of war sold a 360 to me.

In Japan, Dragon Quest!