I have not found this thread very useful. Someone started a competitive thread and while I was writing the following, the mods closed it. They, the mods, may delete the following as not representative or responsive but I will post it anyway. They sometimes get a little arbitrary in the exercise of their authority.
Let me see.
I have my apps divided into screens. There is the newspaper screen. This screen includes apps that represent the things that I used to go to the newspaper for as a child. Movies, TV, funnies, weather, baseball, football, other sports, etc. It also includes Bloomberg, Walt Mossberg, the NYTimes, WSJ, and USAToday. It includes my RSS reader with feeds for Apple, iPhone, gadgets, IT, Internet, banking, payment card industry, and information security. I do not have room on this page for CNN or MSNBC but this is where they might fit.
I have a travel page. This includes iMaps, AT&T Navigator, TomTom, Metro North train schedule, transit maps and schedules for NYC, SF, Washington, London,, Paris and any city I expect to visit soon like Seattle and Vancouver. It includes two apps that will display my flight itineraries, gates, and status, as well as the FAA airport status and an app to show the progress of flights in the air.
I have a book page. This includes Wikipedia, dictionaries, the Constitution, Computer Desktop Encyclopedia, stand-alone books, many free or cheap, as well as Stanza, Kindle, Barnes and Noble, and e-Reader.
I have a games and toys page for toddlers, children, and teen-agers
I have a shopping page for SplashShopper, Amazon, eBay, Starbucks locator, Starbucks Card, PayPal, banks, iTunes, the Apple Store, VIP Access, and Deliveries.
A utuilities page includes, Air Mouse, Air Share, Logmein, youtube, iClickr, Google Mobile, calculators, scanners for documents and (bar) codes, Remote, battery meter, notes, voice memos, iMagnify, contacts, calendars, clock, compass, camera and photos, etc.
There is a communication page for web browser, Skype, AIM, SMS, e-Mail, Vonage, TruPhone, etc.
There are a few things uncategorized and miscellaneous. Did I mention music, videos, audiobooks, and podcasts. I also have a lot of saved "state," settings, "recents" and bookmarks in iMaps, Safari, and navigation programs, that represent significant value to me.
So my applications are media, news, travel and navigation, communications, computing, shopping, reading, recreation, and control. These, not any single program, represent my top "five" applications.
Oh, and sometimes, I make phone calls.