Monkey Studio is a Qt-centric IDE and supports Qt projects in a number of languages. It seems to be well thought out with the exception of a couple things.
First, rather than using the standard GDB debugger directly, it uses Beaver Debugger–a wrapper for GDB stripped out of Qt Creator. A Beaver Debugger is available for OS X and Windows, but there is no package available for Linux, either in the Debian repos or from the authors.
Second, there is no template to make a Qt project with a form based on a *.ui-file. I'm pretty sure it's not a big deal to create such a template, but it would be nice if it existed by default. Starting with a Qt GUI project and then adding a Qt Form to it is a tedious and (at least for the one time I tried it) error-prone process. This is easily ameliorated with a new template.
The integrated Qt Designer is well done. That along with support for lots of languages (including Python) makes this an appealing option. The fact that it's C++-based means it starts up pretty quickly (an issue with the Java-based IDEs). Hoping that Beaver support improves.
*.profiles seem to be compatible with Qt Creator
Lack of debugging makes this less than appealing for serious work. Debugging is not available at all for PyQt projects–in spite of the good PyQt templates, etc. I really hope to see this IDE develop.