I recently switched from Eclipse to QtCreator and I'm really, really happy with the switch. I strongly believe that statically-typed languages are meant to be written in editors that actually parse and index your code -- I find my productivity hugely enhanced by simple things like "jump to definition" and auto-complete -- but as a Linux user I can't use Visual Studio nor XCode, and Eclipse is a huge bloated mess. QtCreator is relatively lightweight yet supports the C++ indexing features I need. Despite being part of Qt, it actually works great for general-purpose C++ programming.
Anyway, I wrote a .capnp syntax highlighting definition:
This produces similar highlighting to what you see on the Cap'n Proto web site. My approach to capnp highlighting is a little different from your typical programming language, in that I highlight things like "type expression" and "value expression" rather than "string" or "number". For declarative schemas, I find this more useful.
I also wrote an Ekam plugin. Not sure if anyone other than me has managed to get Ekam running, but if so, here you are. :)
Both of these will probably get some tweaks as I start using them more heavily in the near future.
-Kenton