The Apple iPhone packs the Safari web browser, giving full xHTML rendering and JavaScript through a WiFi or EDGE connection. Google Maps is also available for mapping and directions, and a 'widget' system gives you instant access to the information that matters to you. The Heat is a gleaming slider phone with an electrostatic touchpad, but has all the right geeky qualities.
The touchpad is set so you can customize its sensitivity (super, high, medium, low) for navigation through a simple finger tap, which means no more pushing extra hard while trying to navigate through applications.
Through Apple's collaboration with Cingular Wireless, the company has been able to include some interesting carrier services, such as random access voice mail. Random access voicemail is a first that allows you to see a list of all your voicemail messages, showing the caller and the time and date of the call, so that you can jump right to the voicemail you need rather than have to listen to each and every one in turn.
The iPhone v1.0.1 Update also covers a separate cross-site scripting flaw in Safari as well as a memory corruption flaw in WebKit that creates a mechanism for hackers to inject hostile code onto the device. The patch also covers an address spoofing bug in WebKit, the application framework engine for Mac OS X, and a cross-site scripting flaw in WebCore, the HTML layout engine for Mac OS X.
I think all of these programs would be fantastic for the iPhone platform. When it comes down to it, implementation is key when working on such a unique platform / user environment. I think Josh's mock-ups are great and are how I would like to see these programs designed for the iPhone if they were developed! Out of the 5 though, I think the E-reader idea is the best.