A list of Android applications you won't find on the iPhone, and what they do that keeps them off the iPhone. These applications do not require violating the Android security model to use. Given that these applications don't exist on the iPhone, I normally list a couple of them available for the android as examples, and then explain why that category of products is missing from the iPhone.
Alternative app stores - Apple owns the app store, and you can't install software from elsewhere without jailbreaking your iDevice.
Google runs the Android market, but to install software from elsewhere, you only have to change a setting provided by Google. As a result, carriers are starting to set up Android app stores of their own, and DARPA is even soliciting projects to build app stores to distribute apps to the US military!
A new - and very useful - addition to this category just showed up! Alternative interfaces to the standard app store are appearing, including the ability to manages apps from the browser. Most notably, appbrain.com filters spam apps. Both the appstore and the market have them: dozens or hundreds of nearly identical apps that change nothing but data. Various soundboards, ebooks (not readers, just books), ringbacks, image collections, etc. I can now search for book readers without getting flooded by hundreds of "apps" that are just public domain books bundled with a throw-away reader, something I could never do on the app store.
google voice, Dolphin, K-9 - because they duplicate functionality in one or more Apple apps.
In this general category are browsers, contact lists, phone dialers, mail readers and similar things. Oddly enough, music players are ok, but without background play don't really compete with iPod. It'll be interesting to see what happens to the ebook readers when Apple's comes out.
Slidescreen, Homepage - because they change the look and feel of the phone.
These are just the most popular of the home screen replacements available on Android. Homepage - at the very least - supports themes, which are also generally missing from the app store.
In other words, while iPhone users can only get the experience Steve Jobs wants them to have without jailbreaking their iPhone - and for a lot of people, that's more than good enough - Android users have almost always had a choice. An interesting new twist is that iPhone home page emulations and themes are appearing, so Android users can have the same experience, without the limitations!
Pinch-to-zoom from 3rd party apps - because only apple apps can use pinch-to-zoom.
This one is just to strange, but an app was rejected for using the standard iPhone pinch-to-zoom functionality that most Apple apps use, because - well, only Apple apps are allowed to do that. Apparently, third party vendors aren't allowed to give you the experience steve jobs wants you to have! I fully expect this one to be overturned soon.
Locale - because it has plugins, and toggles system settings.
Locale is a cool app, allowing you to set up a number of conditions - the built in one is location, using GPS, phone and wifi - which can then cause events to happen, with the builtin events being toggling various phone settings. I use it to provide a more suitable wallpaper at work, and to turn bluetooth off and wifi on when I got home.
Apple doesn't let developers toggle system settings at all. This might be part of the previous issue in that it duplicates the provided settings application, or it may be a more general issue. Their are a number of Android widgets for toggling power consuming services from the home screen. Google included a nice set in the 2.1 release of the OS.
Locale also provides a plugin interface for both conditions and actions. Apple disallows plugins, probably because it would let developers deploy code without going through the app store. While Locale is free, the plugins may or may not be, which is an interesting way of monetizing the project. Locale plugins include things like detecting specific wifi networks, doing web requests, or running ASE scripts. Speaking of which...
Python, Ruby, Beanshell - lets users write code.
Google has released the Android Scripting Environment, which bundle up those interpreters, allowing developers to quickly prototype some applications. Apple is pretty much dead set against letting people develop on the iPhone, even in such a limited way.
Frink, Clojure, Scala - Also lets users write code.
These are language that run on the JVM - but aren't Java - instead of a scripting environment. Again, Apple doesn't want developers working on the iPhone. To bad - no quick checking out of an idea on your iPhone.
Pascal, Basic -Yet more programming languages.
These are classic langauges that have been ported to Android. Possibly they are ports of JVM software, but unlike the previous category, the language wasn't designed to run on the JVM.
Wifi signal sniffers - for using unauthorized frameworks. These were pulled on March 4th, 2009.
Babes, Wobble - for having overtly sexual content.
At least, that's what the letter developers got when their application were pulled recently. Those that did, anyway - if you were a large enough company, your apps seemed to have been overlooked. For such, Steve Jobs himself recommended that you buy an Android phone.
Ports of Android applications - ?????
No, that's not right - the ports are there. But the developers that mention the android version are being threatened with removal unless they change that. So you won't know they are ports. The reason I can come up with that puts Apple in the best light is that Apple think their users might be confused into thinking those aren't iPhone apps.
Android magazines - ?????
Apple has banned a magazine app - because it was about android. They only conclusion I can think of is that Apple is afraid of their users learning about the competition because they know it's a better choice for many users.