In touchscreen, do not even bother to consider the Symbian OS, since their S60 5th edition was a terrible failure. BUT we haven't seen what the Symbian 3 is capable of. Also, the Iphone OS only works for the Iphone, and I can say that their phones lack some basic features, like bluetooth and USB connection. So, i think the Android is the best. Also, it has the highest market share as of the first quarter of this year. Android has 33%, Blackberry has 28%, and Apple OS has 23%.