I recently accidentally re-activated my old FB account from high school (deactivated 2010). It's all still there. It's more like "unpublishing" your account than really "deactivating" it.
[1] Sorry for the google ref link but I have fb hosts blocked and couldn't find an easy way to just copy the actual link: https://www.google.gr/url?sa=t&rct=j&q=&esrc=s&source=web&cd...
The link to permanently delete is only found inside help articles.