For any phone
I guess you have apps for nearly anything nowadays! Personally it's getting hard to find nice ones just by browsing around so i think it would be a cool idea to list your favourite apps and list what they do! That way you don't have to browse around endlessly and aimlessly
So what is your favourite app?
I personally love the standard apps for twitter and msn but i´ve grown attached to my weather app because the weather here can change so rapidly. Other than those i have some game apps because the standard games on my phone are not exactly fun to play!