I've only ever indulged in Destiel myself. I've never really had a thing for sibling incest (though I have my moments like that one time I went looking for Jimstiel omg no shame! Holy butt the Cas/Dean/Jimmy fics though talk about whoaaaaaaaa) and Destiel was more personal for me cause I familiarize better with Cas. XD I don't have an issue with it though. Actually, if I'd come into Supernatural before Cas came in, then I'd most likely ship Wincest. But Cas stole me away! The bastard.
But I love Sam. Sammeh is mah babeh. If I do ship him, though, it's probably with Gadreel. >_> Just because... I dunno lol.