If you mean by top 5 in general then it is different from time to time but right now the top 5 for me is .
1-chrome ( was firefox and thats changed 3 month ago )
2-firefox
3-steam ( simply I can not life without playing smite
)
4-Malwarebytes
5-Utorrent ( my main source for downloading ) .
this top 5 is arranged randomly .
P.s : i think this thread should be removed to off topic or something .