Lina x Gourry. I like Lina to be the man in that relationship, thereby making it hillarious & ironically more likely how it would be if they ever actually hooked up. I'm also totally down with bitchy redhead dominatrixes.
Xellos & Lina. I like it when he gets her all flustered up. A relationship between them would be impossible, & if it wasn't, it would be taboo, & that's one thing that makes it appealing. The other is that every time he gets kinda flirty, it reminds me of the Pretear manga.
But for reals, I prefur sexless, romanceless relationships with lots of comical arguing & fighting.