I would choose the Bold, which I own
For Multitasking, Email and typing the Bold wins hands down! I heard the Iphone is cool at first but then it loses its appeal
You might be thinking that on BBF the opinions might be biased, but this is a great article that compares all of the great smart phones out! Ultimate Mobile OS Showdown: iPhone vs Android vs webOs vs Blackberry vs Windows Mobile vs Symbian | Maximum PC
When we added up all the qualities we prefer in a smartphone OS, such as multi-tasking support, a good selection of bundled and PIM apps, fast operation, and messaging prowess, we realized that BlackBerry OS is a hair more powerful than iPhone 3.0 OS. Overall, apps loaded faster than they did on the iPhone 3GS. For those who want a rich selection of apps and better media and sync support, the iPhone is a better choice, but we really need multi-tasking in our OS."