GDP stats for all nations 2006
USA GDP is #1 at $13T+
Next closest is Japan at $4.8T
Germany 3rd at just under $3T
UK at a hair under $2.4T
France at about $2.3T
China is at about $2T
So the USA's economy is essentially as large as the next 5 largest economic powers.
Here's the link to the site with all the stats. This site also has links to almost every nation's growth stats from 1980 - 2006. Fascinating to see China's economy almost double in size since 2000. Also interesting to see the start-stop process of the pre-capitalist years, symptomatic of communist economies. Another interesting nation is Japan, seeing their bubble and then their burst. I am still checking out a lot of numbers here. Careful because some of those decimal points are hard to see.