You make an interesting point. I hadn't really thought about it, because my personal organizational system is something like 'stack all the RPGs on the desk/in the closet'. I don't really pay attention to the spines, because I go through it all top to bottom (there's not that much).
You've got me thinking though, because I just got done publishing my first game, and I opted for coil bound. While this obviously prohibits spine text/images, I like that it lays flat when open, unlike most traditional binding options. Maybe if I'm the only one, mine will stand out (It's the one with the coil deals!).
If it's any consolation to Larry, I so-much intend to have a spine that I've been noodling around with publication company names that include logotype that will look good on a spine (ex: the Z-D logo for Ziff-Davis books). I have already (mostly) settled on an equally spine-worthy logo for the GLASS library. And, hell, I use an anagram game, which converts nicely to vertical type! I'm spine-committed, baby! All in!