@bilal
like 2fast said, a new application for the iPhone is launched pretty much every single day. so there are hundreds of applications. basically jailbreaking allows you to install 3rd party applications. so like i said, the usability of the application is only limited by ones imagination. you can find applications that record video, audio.. even applications that will listen to the song thats playing on your car radio and identify it for you.
i dont know where you are looking for prices of unlocked iphones, but they are abundantly available on ebay for $450.
here's my advice. find a friend who owns an iPhone and USE IT. the accelerometer is not something that can be described in words. it's an experience all in itself. and NO OTHER PHONE that one can buy has an accelerometer, or a multi-touch display. multi-touch is very different from a simple touch screen interface.
forget the forums and words of mouth. just find someone who has an iphone, and use it. you'll see what the hype is about.