According to an article on IGN, Gamespot reveals

Sony' s latest console saw a low attach rate of 1.5 games per console sold, with Madden NFL 07 and Resistance: Fall of Man the best-selling titles. Wii saw a " surprisingly good" attach rate of 3.0 games per system sold. Legend of Zelda: Twilight Princess and Red Steel were the top sellers at GameStop and EB Games.

link

http://au.wii.ign.com/articles/747/747099p1.aspx

Well thats a better attach rate then Japans ps3 launch but considering that sony really need to sell games to get some cash flow going this isn' t great news for them.

They do predict a growth in attach rate once the ps3 gets into the hands of real gamers but with the crappy selection on games (gundam, genji and untold have had very poor review scores) i don' t see this improving in the forseeable future