Nielsen have found that, after the Android Market, Facebook is the most used app (How else will people download it?). This is among people aged 18 to 44, so therefore covers a large array of ages.
Of course, a lot of the top apps are Google’s own, such as Gmail, Google Map and Youtube. This would make sense, considering they come with almost every Android device out there. Youtube is also an extremely popular app for all ages.
The most popular game, somewhat unsurprisingly, is Angry Birds. Strangely, Angry Birds appeals more to 35 to 44 year olds than the other two age groups.
Something that shocked me is that there are no Twitter apps on this list, official or otherwise. Another thing is the appearance of Advanced Task Killer Free, which isn’t necessary to use on the Android platform.