When it comes down to it I don't think they would go that way, EXCEPT every time I let my rational side take charge SPN does something that makes me take notice and go 'OHHHHHH!'.

it's the ties of family that Sam and Dean will choose over everything else.

That right there is the way I want the series to end, because as much as the myth arc and the MOTW are fun what I'm really here for is Sam and Dean being a family and choosing each other over every thing else.