Sorry for being late to the question asking party, but what is a good reference application (say, maybe one out in the wild, or one that is typical or in use) of DM server?
I ask because we're a ways from using/trying OSGi, the main reason being "why bother"? Sure, modularity is nice, but why rebuild what we have to be OSGi-ish.
So, are there any cool/nifty apps out there that I can reference or look to? If not, what's a good idea for one? i.e. a web service with pluggable features?
The main advantages of using OSGi is component based and service oriented approaches to organize and modularize your applications during development. At this level, Spring DM provides facilities to use Spring within OSGi bundles and to add dynamics within dependency injection. Moreover, at runtime, you don't have conflicts any more between different versions of tools and your application administration is much flexible. No more need to stop the application to update it!
Regarding cool applications, you can find some in the Spring DM distribution and in the source of the book (http://code.google.com/p/springdm-in-action/) . For the later, you can see chapter 6 for application organization, chapter 7 for data access and chapter 8 for Web...