I have an ungodly-huge collection of Christmas ornaments, courtesy of my very generous mother. As I've been collecting since, well, birth...the themes of the ornaments are like a museum exhibit of my various interests. Now that I have children, we're trying to build new "us" memories, so many of my old ornaments stay packed away...but a few do make it on to the tree nonetheless.
Witness part of my Star Trek collection, as displayed by my darling husband. Captain James T. Kirk (TOS) admires rehabilitated Borg "Seven of Nine" (Voyager).
No. This is not at all inappropriate.