To
Gizmo's point about 'FPS' equating to 'simple', this is probably the same distinction I have made, albeit a subconcious one.
I have been a long time fan of Nintendo's Metroid franchise, it was originally a 2D sidescroller with emphasis on exploration. Retro studios then evolved it into a living breathing 3D environment with their 'Metroid Prime' trilogy, and in my opinion they did it perfectly. But that's besides the point.
The Primes are essentially FPS, but they're alot more than that even at the core, they're not just about blasting aliens (Metroid Prime/Halo comparisons are the most popular), they still provide that heavy exploration value that previous Metroid games excelled in, and though the many puzzles in the games are solved with the use of your gun (albeit more than simple pointing and shooting), and in pure FPS style all of the doors are shot activated, these games were still not 'simple' or 'mindless' enough to be considered FPS, so they were dubbed First Person
Adventures. And it delivered the message quite efficiently.
There was also a Metroid Prime spinoff on the DS called Metroid Prime: Hunters, which emphasised online deathmatch, and broke away from the heavy single player immersion of the whole Metroid franchise. This game is more commonly refered to as FPS, though its story has a few exploration elements, the game is pretty much just a catalyst to flaunt the DS's online capabilities for a fast-paced, real-time shooter. Whether people do it consciously or not, many references to FPS are made, I feel, with a pre-concieved notion of being 'simple' to some degree.
Thank you
Gizmo, for rationalising this in my mind

~Ever play http://www.youtube.com/watch?v=Mntnjaw88tE&feature=related?
I've played a demo years ago, loved it

Always wanted to buy it, never got around to it. Story of my life when it comes to games