Of course, Blackberry has a questionable future.
My vote is to go with the ipad simply because it can do so much more than it's competitors. Even if you don't need the additional functionality, you might in the future. (You might even need it in the super near term once you get to using it and realizing all that it can do.)
Like others, I am not an apple person. I'm a PC guy. When people started buying ipods, I ended up with an (awesome) iRiver H320. That purchase reinforced my anti-apple attitude. I have long been an 'organizer' guy and jumped from Day-Timers to Palm pdas pretty early on. I went through a number of them and was pretty pleased, until Microsoft Vista came around. All the sudden, I was having tons of sync problems. This pushed me to a change that I never expected to make. I moved on to an ipod touch.
All of the sudden, I could watch movies on a screen over twice as large as my H320. I had apps that could do everything that my palm would do and tons more. I could actually get online.
A couple weeks ago, my wife, the blackberry user, replaced her phone with an iphone 4s. While she is not over the transition angst, she is definitely loving the new tool. I can tell that she likes it because she has dusted off the ipad 2 and the Macbook Pro that have gone unused since she got them a year and two ago.
My iphone should be to me in a week or so.