I just checked a number of our recent projects to see if we were including jQuery UI on them:

* Arthritis Foundation: no
* Blue Sky: yes
* Gift of Knowledge: no
* Hack Design: no
* Team: yes

It's not clear to me how heavily it is being used.

/cc @jessieay @devonharless @salbertson @frechg @alexbaldwin @brittballard @NealKemp 

I think my preference is to go the other direction and exclude it, only adding it back in when needed. The intention of Suspenders is that we're including dependencies only if we find ourselves using it on just about every project.