It's hard to overstate how successful the iPhone Apps Store is. Check out the latest figures from Apple:

Apple today announced that more than two billion apps have been downloaded from its revolutionary App Store, the largest applications store in the world. There are now more than 85,000 apps available to the more than 50 million iPhone and iPod touch customers worldwide and over 125,000 developers in Appleā€™s iPhone Developer Program.

"The rate of App Store downloads continues to accelerate with users downloading a staggering two billion apps in just over a year, including more than half a billion apps this quarter alone," said Steve Jobs, Apple's CEO. "The App Store has reinvented what you can do with a mobile handheld device, and our users are clearly loving it."

And I want to highlight this little fact (see the bolded bit) because I think it speaks to the single greatest weakness in the Zune platform:

Today, iPhone and iPod touch customers in 77 countries worldwide can choose from an incredible range of apps in 20 categories, including games, business, news, sports, health, reference and travel.

77 countries. Yikes.