They're doing bad in Asia and doing OK in Europe. The competition with the PS3 is hard in Europe, that's why I said "tough". They are number 2 in some countries (like the UK), but overall they're number 3.

PS3 in Europe as of August 17, 2010 : 16 million

XBox 360 in EMEA (including UK) as of November 13, 2009 : 10 million

Sources : http://www.computerandvideogames.com/article.php?id=260424

http://en.wikipedia.org/wiki/Xbox_360#Sales