It's kind of funny when you think about it. I've always felt a little bit outside the mainstream. But as a geek and nerd, we're all outside the mainstream in ways, but I've always felt outside the mainstream there as well. I don't mean to sound like a hipster, that is not something I'm trying to do, none of this was conscious, but here we are.
In terms of science fiction, the two big franchises are "Star Wars" and "Star Trek" and while I have enjoyed both on occasion, neither of them do anything for me on a personal level. I watch something "Trek" related maybe once every three years. While "Star Wars" is something I feel I am going out of my way to avoid at this point. Give me "Babylon 5" any day over that schlock.
In terms of animation, the two biggest action franchises have to be Transformers and Bruce Timm and Alan Burnett's DCAU. Now, I loved Transformers as a kid, but I can't see myself ever watching a G1 episode again unless I plan to rip into it for a review (I just don't like 80's cartoons. At all). Now I did love "Beast Wars" and at some point I'll re-visit that, an Animated was fun. While I will admit that "Prime" has improved since its pilot, it's still one of the blandest cartoons I have ever watched; and don't get me started on Bay's movies. But, I'm at the point where, you know what, if it's based on a Hasbro toy property, I have no desire to watch it.
The DCAU is something I have a complex relationship with. I love "Batman the Animated Series," but hate "The New Batman Adventures." I love the Darkseid episodes of "Superman TAS" but 90% of the rest of that series is just too hokey and corny for me. The first season of "Justice League" and last season of "Justice League Unlimited" are both garbage in my eyes, although I love a lot of what came between. And as for "Batman Beyond," well, you don't want my opinion on that.
And then there are comic books, well, I can't say I'm outside of the mainstream there, for years I read Marvel's core books. But I guess I'm on my way. Superhero comics and I are a hair away from being done with each other professionally. My favorite comic book of all time is "Lucifer" and my favorite recent comic book is "Kill Shakespeare," which engages with me more than any superhero comic book ever did.
I have a weird relationship with fantasy. I love "The Lord of the Rings," and I like what little I've seen of "Game of Thrones." But it's not a genre I usually seek out. Although, I think "The Dresden Files" are brilliant. As far as LOTR go, I just am a sucker for classics, and always have been.
In terms of movies, I still love Nolan's Dark Knight Trilogy and most of Marvel Cinema's output, but you will never see me say any of these are Best Picture material. But then, my favorite film of all time is "Casablanca" so I don't believe I'm outside the mainstream there. I don't know.
I'm not saying mainstream is bad, I don't want to say that, I don't even think it. But as far as my geek hobbies go, I find that very little of what is considered mainstream geek culture strikes that personal chord with me. But one thing I do know about myself, and again, this is not a conscious decision, but the more likely something is made to appeal to a wider group of people, the less I am likely to find personal enjoyment in it. Or rather, I love "Pulp Fiction" and I despise "Forrest Gump."
But, I'll always find something to enjoy. My friends know me, know my tastes, and are always recommending something new to me. Sometimes it has mass appeal, sometimes it doesn't. But most of the time it will strike that personal chord.