Considering the popularity of Twitter and how many people use it (everyone I know, pretty much), I really can't believe that WordPress has not yet created a widget for it. I'm sure a lot of WP users feel similarly. Does WP even intend to ever create one?
In my opinion, WP is already light years behind the Web 2.0 trajectory in terms of the extremely limited selection of sidebar widgets that it offers. It's frustrating, because I am pretty active 2.0-wise. For example, I have accounts with GoodReads, Last.FM, Twitter, Utterz, Facebook, YouTube and on and on -- all of which offer widgets that can't be used on WP domain blogs. What's up with that?
I'm currently starting to use Blogger because it is WAY more widget-friendly. In fact, options are virtually limitless. And you don't have to pay to customize your CSS.
Don't get me wrong, there are some real positives to WordPress. For instance, the last major upgrade was really neat, I think.
Anyway, those are my thoughts. Just some feedback from a WP user.