I'm not sure if this is a fascinating peek at the way we're wired or an obvious conclusion based on reason, but I'll let you decide. Despite the fact that they seem to be polar opposites on Internet forums and comment sections, Android, Blackberry, and iPhone users all end up using mostly the same apps. That's according to an "app discovery service" over on Facebook called Mplayit, which tracked 42,000 visitors and the apps they preferred for a set of "genres." Turns out that for the various categories, the same cross-platform apps tended to be the most popular on the different platforms. Evernote topped the charts for Lists and Notes, Shazam and Pandora were on all three lists for music, and apps like Yelp and Facebook sat high on the chart for multiple platforms. In the end, an app is an app is an app, "app"arently, and it doesn't really matter which platform you're using it on.
There were a few difference of course -- in the "Utilities" section, things were different for each platform. Bump is the most popular for iPhone, Google Goggles was most popular on Android, and Vlingo won on Blackberry. As far as I know, with the possible exception of Bump, those are all platform-exclusive apps. But in general, if an app is available on multiple platforms, a popular app on one platform means it'll be popular on the other. Good to know both for developers (a hit in one place means a hit somewhere else, too) and for consumers: next time you choose a smartphone, the apps probably won't matter as much as the hardware features.