Anyway, back to why I started this article, I think that Sam and Dean having a "happy ending" meaning that they both get out the life, get married and have kids live the normal life, would be the completely wrong way to go in my opinion. Yes, Sam and Dean worked their asses off and even died multiple times in their line of work for mankind, however a decade of them doing what they do and they have became so entwined up in that existence that life outside of it makes no sense for the pair story-wise.
So, anyway, back to why I started this piece I wanted to give you guys and girls my thoughts on how I think the show should end leaving me in a state of happiness or as close as can be considering my baby is no more.
Castiel & Crowley
Sam & Dean
I know I have gone into the details of what I would like to see, however this is how I see the finale actually playing out some specifics. I see Dean on deaths door (specifics I do not mind, as long as it is a serious situation), while on the floor Castiel is over him ready to heal him as countless times before. Dean looks him in the eye and says "it's my time Cas, I can't do this anymore".
While Dean is left dying due to his injuries, Castiel continues the fight with Sam (not sure who or what they are fighting) upon defeating said "baddie", Sam rushes to Dean and starts yelling that he has to stay, there is no life without each other, you know, the typical Sam and Dean back and forth we have seen many a time. Dean continues to tell Sam how he can not continue to do this all the time, at some point they have to die and Dead has had enough and wants the sweet relief he has earned from three decades of of fighting.
Before crossing over, after he has given the Dean speech, he leans in and whispers something to Sam, which we do not hear and also passes him something we can't see. Fade to black, cue Sam knocking on an oddly familiar door, the door opens to Ben, Sam hands him the keys to the Impala and informs him it was his fathers who was a great man (giving him a traditional Winchester speech, we do not hear the specifics of).
"Happy 1st Birthday Dean" is a banner we see hanging above a crib, "Goodnight, Dean" says Sam and the show ends, a nice way to wrap it up, considering that was Dean's first ever words in the show. Sam's now wife, leans over Dean's crib an starts to sing this...