GlobalMax - 2:10 pm on Mar 9, 2011 (gmt 0)
I would go for site/page
As for last forward slash, the page should not have it as it denotes folder.
Here is the counter-argument (in favor of site/page/):
I do use a trailing slash, even below the top-level. If provided with site/page, I 301 to site/page/.
Note, however, that I think of it more as site/topic/ than site/page/. URIs really indicate resources, not pages and folders.