we use tastypie: django-tastypie.readthedocs.org

for the most part it works really well. for a while the development was sort of stagnant/dead while the developer was looking for people to take it over. recently (2-3 months ago) a team has formed around the project and is actively maintaining and pushing new features again.

Pyramid has nice decorators that make building rest services a breeze - there is also cornice project for pyramid which can even make documented apis.

Tornado. But maybe that's because I come from an event driven background.