Although boasting about the size of one's app store has its place--really it's the quality of the apps that matter and nothing beats those "big titles" that people want and use.
PCWorld has done an interesting analysis of Apple's top 35 apps to see how the other platforms compare. Android, comes the closest, offering all but 3 of the top 35 apps on the iPhone. Their biggest gap of course is in games--something we've pointed out before. Next, however is Windows Phone 7 which offers all but 8 of the top 35--beating out Symbian and Blackberry (guess WebOS wasn't worth looking at). That's not too shabby for the new guy in town who's been in the market a little less than seven months.
Part of the difference is Microsoft has been very aggressive in courting Apple developers to either switch or port over their apps, often offering financial incentive to do so e.g. covering the cost of development. Combined with the Xbox LIVE gaming system and their relationship with the "big" developers there, Microsoft has made tremendous in-roads into taking away any "exclusive" app that the iPhone may offer (and more often than not, the Windows Phone version looks better).
We may not have the numbers, but we have the apps.
Source: PCWorld/Yahoo News; Thanks, hd7guy, for the heads up