I'm pretty sure that total software sales are related (probably through a logarithmic function) to the number of consoles sold; what this means is that (although the attach rate may get progressively worse) the Wii's higher hardware sales will lead it to have higher software sales regardless of what "big games" are released.

Wii, by far.
PS3 and 360 will be close. It depends on whether the PS3's big exclusives (like Final Fantasy XIII and Gran Turismo 5) come out this year, or whether they are released in 2009, and who gets more sales on multiplatform games.

Worldwide software? Wii, easy. 360 can't keep up with the Wii in software sales from January having a clean slate at that point, due to Japanese software sales, imo.

Could be wrong though.

Others software from Week Ending Jan 5, 2008 - Mar 15, 2008

Software Totals:

Console	Year	Total
	7,579,697	-
	6,929,737	-
	3,701,157	-
	3,358,537	-
	1,333,058	-
	656,044	-
Total	23,558,230

Edit:

To remove bundled Wii Sports

VGChartz Hardware data for the period 05th Jan 2008 to 15th Mar 2008:

2008 - Wii by a lot
2009 - Wii barely over PS3
2010 - PS3 by a decent margin over wii
2011 - Same as above
2012 - PS3 by a lot
2013 - PS3 by a lot
2014 - PS3 by a lot
2015 - PS3 by a lot

software: wii>360>ps3
hardware: wii>>>>ps3>360

ps4 will be out by 2011...ps3 software will still sell past that, but not at as high a volume...also, hardcore gamers will be the ones to jump on the next gen ps4/720/wiihd, so hardcore consoles like ps3/360 won't see high software sales after their successor comes out...wii will continue to see high software sales like ps2 does after wii2 comes out as casuals don't upgrade as fast and will still buy more games

i don't see ps3 ever beating wii in software sales, and i haven't seen any data or logic that would back up an argument that it will beat the wii in software sales

EDIT: Haha, I see you said software sales. I'm a plonker, ignore everything below!

Wii will sell the most naturally, with PS3 in second place and 360 following a fairly distant third.

Lifetime sales?

Wii - 80 million (will be dead by 2012, with a slowdown in sales from '09 onwards due to lack of uptake from hardcore gamers, and the kids will have a new fad to play with...)

PS3 - 100 million (assuming a longer lifespan into 2013, its uptake as a blu-ray player and it actually taking off in Japan. A lot of if's I know!)

Xbox 360 - 50 million (Will be outsold in the States by PS3 from '08 onwards, with mediocre sales in Europe and minuscule sales in Japan. Microsoft will release their next console end of 2010 possibly killing the 360 prematurely)

So everyone will be pretty successful compared to previous gen (except Sony, who'll just do well again...)

Congrats!  You got a BINGO!  Come collect your prize! (tho next time i'd like to see you do it without the free space...)

@Fastrabbit09

Holy shit fastrabbit, you just made me laugh so hard!