"Anywho, romance is much more interesting."
You think so, huh? You must not have read many good non-romance mangas, then.
I voted platonic, although really, I'm down with any kind of relationship in manga as long as it doesn't become a plot tumor. Since romantic relationships have the highest chance of this, I tend to avoid series where romance is a big focus. Aside from that, platonic relationships, I think, are really beautiful and seriously underrated, and sex and sexual relationships tend to be way hyped up, in my opinion. Of course, sexual and romantic relationships can be really strong and beautiful; by no means am I denying that. But isn't the ability to love someone without any physical attraction also beautiful?
These are some of my favorite non-romance mangas that have great examples of nonsexual relationships:
Pandora Hearts: There are so many different types of relationships in this series, but the master-servant (though more like best friends) relationship between Gil and Oz is really beautiful. Their devotion to each other is extremely touching and has allowed them to overcome countless obstacles.
Fullmetal Alchemist: The bond between brothers Ed and Al is a great example of familial love. These two have been through hell and back together, yet their relationship always remains strongly intact. A benefit of their familial bond is that they can fight with each other or disagree, and yet they always remain connected.
Natsume Yuujinchou: This manga is deliberately non-romantic but is all about forming relationships. There's so much here that it would take ages to examine all of the relationships presented in this manga, but there's a good many of them, all of which are significant in some way.
Anyway, there are loads of other examples in manga, but you get the idea. Personally, I'd like to see more portrayals of different types of relationships, but I suppose that's why I'm a picky reader!
For me, my strongest relationships are with my family and my best friends. Heterosexual Life Partners FTW!!