The Widget Framework allows you to easily modify the look of your sidebar and re-order the position of the Widgets. There's also add-ons released that can add functionality to the sidebar as well as the ability to create your own widgets.
This is one thing on IPB i love...you can easily just comment in the status feed. With XF, you can read the status but to comment you have to go directly to that person's profile to comment so it gives you an extra step.
Hopefully someone will come up with an add-on to knock the extra steps out the way