Source:
http://www.neogaf.com/forum/showthread.php?t=311356 :
The PS3 outsells the 360
without MGS4? The Wii sold
675K?! The 360 hardware constrained...maybe...possibly...
HW
PlayStation 3 208.7K
PlayStation Portable 182.3K
Xbox 360 186.6K
Wii 675.1K
Nintendo DS 452.6K
SW Top 10
Top 10 SKU's May 2008 Rank # Units
(includes CE, GOTY editions, bundles, etc.)
360 GRAND THEFT AUTO IV TAKE 2 INTERACTIVE (CORP) APR 2008 1 871.3K
WII MARIO KART W/ WHEEL NINTENDO OF AMERICA APR 2008 2 787.4K
WII FIT W/ BALANCE BOARD NINTENDO OF AMERICA MAY 2008 3 687.7K
PS3 GRAND THEFT AUTO IV TAKE 2 INTERACTIVE (CORP) APR 2008 4 442.9K
WII PLAY W/ REMOTE NINTENDO OF AMERICA FEB 2007 5 294.6K
WII SUPER SMASH BROS: BRAWL NINTENDO OF AMERICA MAR 2008 6 171.1K
PS2 IRON MAN SEGA OF AMERICA APR 2008 7 130.6K
WII GUITAR HERO III: LEGENDS OF ROCK W/ WIREACTIVISION (CORP) OCT 2007 8 116.8K
NDS POKEMON MYSTERY DUNGEON: EXPLORERS OF DARKNESS NOA APR 2008 9 107K
NDS POKEMON MYSTERY DUNGEON: EXPLORERS OF TIME NOA APR 2008 10 102K
So it's more than likely a chunk of the sales are to people who will never buy games.
Hard to really infer anything from them because of that & probably the same reason why MS keeps talking about "attach rate" in all their NPD press releases.