I went through this same debate a few months ago, and did a ton of research. I agree with the comments above about assessing your needs, usage and whether you can afford the (usually mandatory) data plan for any "smart phone".
If you can, the next thing to consider is the carrier's coverage in your most frequent usage areas: I live in the US Northeast and, unfortunately, once you get outside Boston and other major cities (which I do frequently for work), AT&T's coverage just sucks. That is the primary reason I did not get an iPhone, because all my friends who have them absolutely love them.
So, I was stuck with Verizon (which isn't necessarily a bad thing.)
I went with the BlackBerry Storm 2 for various reasons. While I like the device just fine, I will say that if you're not a techie who likes to fiddle with and keep up with your phone, I don't think a BB is necessarily a good choice. For instance, we all got an operating system upgrade pushed to our phones last week and, for many many people, if they installed it their phones were really messed up (this happened to a few friends of mine; I held off pending reviews of the upgrade). People had to go through a lot of hassles to downgrade and/or otherwise "fix" their phones. Also, if you're not getting it for work and/or your work doesn't have a BES (Blackberry Enterprise Server) as mine does not, I thing I'd suggest steering clear of the BB. Again, I like mine fine and have found work arounds that are fine for me, but if you want a phone that just lets you do what you want to do without finding work arounds, I'd go with something else.
Coincidentally, the first Droid was released the day before I bought my BB. I steered clear mostly because it was brand new and I'd heard people didn't love the keyboard. That having been said, I know several people who have the Droid and without exception they all love the thing, and say they have gotten used to the keyboard.
I also hear very good things about the upcoming Droid Incredible, as well and, as someone else said, the iPhone is coming to Verizon before too long.
Oh, and there's the Palm Pre which is now on Verizon. I was pretty jazzed about the device when I first ready about it but, unfortunately, it seems the reality is a little less spectacular than the hype. Still, I know a few people who have it and they all do seem to like it fine.
Sorry to be so long winded, but hope all this helps. Good luck!
