I'd like to nominate Overgrow.com 
I think we have taken site integration to the extreme. Our front page, including the in-house CMS, is all tied in using the same database and pulling from the forums. It uses a custom caching routine so as not to slow the site down. The Photo Gallery is another in house application that is entirely integrated with vB-- each vB member has their own gallery that they manage and is accessible from each of their posts. We have other things like myOvergrow and the Garden Profiles that you can't use without registration.. we're also the original home of Karma. 29,000 members and nearing 1 million posts, we've been using vB since 1.1.
home: http://www.overgrow.com
forums: http://www.overgrow.com/edge
*** ADULT CONTENT *** not porn but it is not for minors

I think we have taken site integration to the extreme. Our front page, including the in-house CMS, is all tied in using the same database and pulling from the forums. It uses a custom caching routine so as not to slow the site down. The Photo Gallery is another in house application that is entirely integrated with vB-- each vB member has their own gallery that they manage and is accessible from each of their posts. We have other things like myOvergrow and the Garden Profiles that you can't use without registration.. we're also the original home of Karma. 29,000 members and nearing 1 million posts, we've been using vB since 1.1.
home: http://www.overgrow.com
forums: http://www.overgrow.com/edge
*** ADULT CONTENT *** not porn but it is not for minors
Comment