You're right in that Facebook isn't very clever... on the surface. Its unique, and actually, the concept of a facebook has existed for quite a while. Its not a widely known idea though, and that's kind of what made the name work. Its straight forward, but for most people, original. Microsoft is also very simple, but its biggest strength is it was in a market without much competition. Standard Oil NEEDS to be obvious for success.
It's best to compare the name Gamers' Plane against other RPG (or tabletop) gaming sites or companies. Think about our favorite developers. The least creative I can think of is Monte Cook Games, and its success is based on the name Monte Cook (being an amazing designer). Otherwise we have things like Catalyst, Wizards, Pinnacle, Evil Hat. In sites, we have a bunch of names specific to certain systems/genres... not too much out there that's broad. One example who's name I love is Obsidian Portal (my direct competition). Obsidian Portal gives this impression of entry to any place, its a very strong, memorable name. Gamers' Plane is much softer. It's easy to become comfortable with it, but it doesn't have a strong first impression.
I really wish RPGNexus.com was free, or has a listed contact. I'd buy it from them.
Let me be clear. I don't hate Gamers' Plane or anything of the sort. I just know, from experience, its an average name. If I keep it, it's success will be based entirely on what you guys make this site to be. People will come here for the great community that already exists, and its one of the reasons I'm considering rebranding now. Other people might shy away, at the work of having to rebuild the name, but with fantastic users like you, my work will be severely reduced. I've got a visual rebrand of Gamers' Plane coming up, and so I figured now's a good time to look over the name as well, given we're still small enough to consider it without severe repercussion.