Many people consider the iPad a bigger version of the iPhone or iPod Touch, and admittedly there is overlap in functionality. But I do not see Apple purposely producing a product that directly competes with their iPhone and iPod cash cows. With that in mind, let's look at where these devices will cross paths and which one has an advantage.

Convenience

Since the iPhone is you know, a phone, it will often never leave your side. It rules as a go to device if you want to get access to something right now. The iPad's size while svelt, won't exactly fit on your bottom line. While more convenient to drag around than say a laptop, the iPad won't replace the iPhone as the go to device when needing to know the population of Kazastan during a conversation, or an replace an iPod when working out at the gym.

Usability

While the iPhone has greatly improved, if not necessarily reinvented, the user experience for a smart phone, the screen is only so big. I have tried using the iPhone as a ebook reader and personal video device and I can only stand the eye strain for so long. Even viewing webpages for any extended period of time can become bothersome on an iPhone or iPad Touch. The iPad's 9.7 inch screen, nearly 4 times larger, will allow for much more pleasant extended viewing sessions. The larger screen will also allows us fat fingered types to navigate apps easier and allow developers more screen space to display data.

Cost

Compared to a ?99 iPhone or a ?199 iPod Touch, the ?499 for the 16GB iPad may seem steep. But we must remember the the iPhone price is subsidized by At&T and requires a 2 year contract to acquire that price. Also the ?199 iPod Touch is only an 8GB model, the 32GB will cost you ?299. Given Steve Job's statement of the iPad being positioned between the iPhone and the MacBook in Apple's service line up, we should also compare the iPad's price to the ?999 cost of a newbie MacBook. While not really exactly cheap, ?499 for a 16GB iPad isn't unreasonable.

Apps

Since the iPad will run nearly all iPhone and iPod Touch apps, there won't be deficiencies in applications at launch time. If you have a large library of apps in iTunes, it is possible to use these on an iPad without repurchasing. The iBook Store and iBook app will be limited to the iPad, and as developers come on board, exclusive iPad only apps will begin to appear. The price premium for an iPad optimized app is still unknown, but I would not be surprised to see an average price of ?4.99.

Final Thoughts

Will the iPad cannibalize sales of other Apple products? For those who do not necessarily currently own an iPod Touch, or don't/can't get hold of an iPhone, investing instead in an iPad could be a logical move. But since you won't be jogging with your iPad to listen to music, or answering phone calls with it, I won't see sales of iPhones and iPods being affected much. I will be very curious to see the numbers on people who bought an iPad and also own an iPhone or iPod Touch versus those that don't.