As of last Thursday night I am an official licensed minister in the Evangelical Chruch of North America. That means I can marry people, bury people, give them communion in church without any red tape and baptize people with the "official" blessing of the denomination. I really could have done all of those things before, but now I carry an implicit stamp of support from the denomination.
Denominations are great. Sure, they provide buttloads of red tape and reports and seem to be full of busybodies...but they are also full of really godly, wise men who encourage me and promise to pray for me and support me and keep me level headed; I do the same for them. Doug Padgit once compared a denomination to a family, with all the baggage and all the great stuff that goes along with that.
So that's it.