Yes, main component for one of my sites, and no forum for the other. Haha.
Yes, I have thought of having a swap, and was planning on doing so, until I realised that my wordpress site couldn't be integrated into the users with xenforo very nicely. Needless to say, I left that idea in the dust, I'd never want to make a client register twice. (That and it seems weird)
My site started as a forum, but the community clearly needed more functionality. So I added:
wiki to prevent knowledge to be lost within the bulk of threads
an image gallery for photo's to be uploaded
a video gallery for documentaries and user uploads
a document archive for scientific studies
blog for opinion articles
social groups for specialistic community discussion. technically still forum.
chat for direct interaction
news article directory so that users can stay up to date on latest events
reviews directory for companies, products and services
question and answers
Now I am trying to replicate all vbulletin addon functionality that in xenforo. It's a large project but doable.
Forum is still the main component of my site, but other components are taking an ever increasing role. Mainly because we used to have forum to cater for everything from news, opinion articles, images, video, Q&A etc. But nowadays people are used to have much better functionality dedicated to the purpose. It no longer suffices to use forums for such.
I think its essential to give users a more integrated functionality instead of forum with a lot bolted on or forum with addons. I will rather provide a complete experience of which forum is an important factor.