Hello sanket-soft,
First off, I would like to ask, what will you be using the phone for? Is it going to be for leisure/personal use or for work/business? If you're looking for a phone to use for yourself I would recommend the iPhone. My wife has the new iPhone 4 but I look at this device as a cool toy/gadget to own.
That said, I believe the BlackBerry is the right tool when it comes to Enterprise/Business. From what I recall, the BB (BlackBerry) devices and services are readily available from more than 200 carriers around the globe. Even though the iPhone has a sleek user interface and a myriad of applications I believe it's still missing the tactile keyboard required by speed typers, battery life etc.
I currently own the BlackBerry Torch 9800
http://us.blackberry.com/smartphones/blackberrytorch/ and like Artashes it was a toss up between a BlackBerry and the Palm. If you're looking to mix business with pleasure
I would go with a BlackBerry and an iPad on the side
. Also, it might not be a major factor but another nifty application is the BBM (BlackBerry Messenger) which is free instant messaging with other users who own a BlackBerry. Think of it as a chat software such as MSN, Yahoo etc but the plus side is when communicating through BBM the data is not charged but these days most carriers are providing respectable data plans 1GB-6GB of bandwidth a month which should be more than ample.
When you come to a decision please update us and let us know what you got and why