Skylar and Walt Jr. (assuming they survive) find a video from Walt, made before he died / got arrested / fled the country entirely. It begins, “To all law enforcement agencies, this is not an admission of guilt. I’m talking to my family now …”
In contrast with the opening scene of the series (where he makes a similar video), he is not at all panicked or frantic. He is calm, relaxed - and very, deeply sad. The show ends with Walt’s final message to his family.
45 minutes and 26 seconds of Badger and Skinny Pete talking Babylon 5 versus Deep Space 9. On the coffee table, between the beer bottles and the bong, is a newspaper. For five seconds in minute 37, it is clearly visible. If you freeze the video and focus in closely enough, you can just barely make out a one paragraph summary of what happened to everyone.
As I suggested elsewhere, (if they aren’t going to ‘Newhart’ it back to ‘Malcolm in the Middle’):
Skylar and the kids board a plane to safety. Walt is alone in an airport parking garage with the ‘go bag’ when Jesse and Hank converge on him.
Jesse shoots Walt in front of Hank.
Hank rings up Gomes and says “Heisenberg’s been shot. Round up the usual suspects”.
Jesse & Hank take the cash and fly off to Grand Cayman as the beginning of a beautiful friendship.
That, I’m afraid, is not going to happen.
Jerry wakes up in the dentist chair, tells Tim “I just had the strangest dream, and you were there and… hey are your pants unzipped? AHHHHH! I SHOULD HAVE KNOWN WHEN I SAW THE PENTHOUSES IN THE WAITING ROOM”
Well…
Crap. 
Walt takes the ricin pill just before walking into a confrontation with the Nazis/Madrigal people/whomever, assuming he will die or be captured. The ricin is insurance he won’t be enslaved like Jesse, at least not for long, but ricin does take awhile. There’s a shootout, but somehow he lives and somehow Skylar and Saul show up, and they recover his money from the Nazis. Walt then has everything he wanted. And dies of self-inflicted ricin poisoning. :smack:
Or he frees Jesse, who immediately kills him. That’s for Jane, bitch.
Or Frankie Munez shows up with a go bag and they flee, Malcom becoming the new Jesse.
Walt attacks the Neo-Nazis with his assault rifle. Through his sheer stupid luck, he manages to take them all out while Jesse watches. He turns to Jesse with the intent to finally kill him, and boom, Lydia, who has been shielding her eyes from the violence all this time (it’s just business), sees the opportunity to take over the empire for herself. She shoots Walt in the back of the head and offers Jesse partnership. He declines and walks away. Roll credits.
Never watched the show, but that would be an awesome ending!
Walt wakes up in a messed-up bedroom, stumbles out the door, and sits down at the breakfast table with his family from Malcolm in the Middle.
Hank comes back as a zombie & eats Walt, & we come find out Breaking Bad is part of The Walking Dead. 
The driver of the red van turns around to face Walt- and it’s Bogdan (former owner of the car wash). He smiles at Walt and drives directly to the police station.
I would love to have a ghost sequence borrowed from the “Richard of Gloucester, despair and die!” sequence from RICHARD III in which the innocent and not-innocent victims of Walt visit him while he’s in a real fugue state.
The fugue state could work and it’s a callback to Walt’s earlier lie about being in a fugue state. We all know how much Gilligan likes callbacks.
To get Walt into the fugue state, I’m thinking somehow he ingests the ricin. How long has that ricin been in the vial? Organics break down and become less potent over time. I’m guessing ricin proteins also become less effective. Thus, a previously lethal dose of ricin might, over time, only be enough to wreck your guts and leave you wracked with unending pain.
Another consideration is most shows with a criminal anti-hero protagonist can’t “get away with it” and have the protagonist completely succeed at the end, especially when there are innocent victims. The writers just can’t condone that sort of immorality. So Walt needs to get some sort of come-uppence, if not true justice.
Speaking of callbacks, Walt coldly letting Jane die was a particularly striking and memorable scene. How great would it be if Jesse abandons a ricin-wracked Walt to die in the pit that Jesse was caged in?
So here is my 100% serious prediction of how it ends. Walt shows up at Grey Matter and gets Elliot and Gretchen to use their corporate influence to get the DEA to back off Skyler and also do what they can to quietly help Skyler and the kids. Perhaps there’s a revelation of past wrongdoings that the Schwartzes inflicted on Walt, which he can use to get them to cooperate.
This resolves Walt’s goal of providing for his family and frees him up for vengeance. He gets the gun and the ricin and gathers intel on his target, Jack Welker.
Walt plans a meticulous operation to setup a strike on the Nazis where they least expect and succeeds in gunning them all down. Perhaps Todd dies protecting Lydia and as Lydia yet again slips away, we hear Todd tell her he loves her with his dying breath. It is ambiguous if Lydia didn’t hear him, or she only pretends not to hear.
In the chaos of the battle, Jesse gets free and gets the drop on Walt, who is out of ammo and on the ground, weak and helpless, but triumphant. Wielding the snub nose revolver that the Nazis recovered from the desert, Jesse challenges Mr. White to “talk his way out of this one, bitch”.
To which, Walt simply laughs. “Go ahead and shoot me, Jesse. If the cancer doesn’t get me, I’ve ingested this vial of ricin! (throws empty vial to ground, then struggles to draw breath) Heisenberg’s already a dead man. (pause a dramatic beat) Bitch!”
Jesse, never one to follow instructions, instead tosses Walt into the pit, locks it and covers it with the tarp, leaving Walt to die in the dark, alone and forgotten, just as Walt left Jane to die.
Walt realizes the ricin is no longer potent enough to be mercifully quick, enters a fugue state, remembers his victims in a soliloquy and we see Walt’s physical suffering overlaid with the suffering of all his victims, allowing the viewer to draw parallels as appropriate. Fin.
Yeah, although flashback scenes with a bunch or characters from previous seasons returning is kind of overdone.
Still, I may be sentimental, but I would at least like Walt to understand the suffering he’s caused, and what it means. At the moment, I don’t think he really understands that he’s done anything wrong. He understands that everything has gone wrong, and that he made the wrong choices, but he still thinks that he was right to do it, he just didn’t go about it correctly.
Richard III always knew that he was evil, he just embraced it. Walt doesn’t seem to quite get the point.
Walt barely choking down his last meal before his execution…Roof Pizza with “53” spelled out in bacon…and a bottle of Schraederbrau.
This prediction isn’t about a final scene but more of a final important event.
Someone is definitely ingesting ricin. (Either that, or Gilligan is deliberately fucking with us.) Possibly several someones, but I’m not sure. Consider the potential symptoms:
We’ve already had a description of bloody vomit on the show, when Badger and Skinny Pete were talking about Chekov. The vial of ricin has long been referred to by fans as “Chekhov’s Ricin”, a reference to the literary trope of “Chekhov’s Gun”. Ingested, ricin can produce bloody vomiting. In the Star Trek story, the crew is eating tulaberry pies - until Skinny Pete objects that tulaberries are from the Gamma Quadrant. Badger says, ok, fine, they’re eating blueberry pies.
What else is blue?
According to Wikipedia, “A dose the size of a few grains of table salt can kill an adult human.” I wonder if it might be even more deadly to those with weakened systems, such as meth addicts. (I know it’s not a pathogen; I just mean their overall health, not their immune system specifically.)
So we have a story, referencing a famous trope about foreshadowing, which itself is linked with the ricin, which talks about someone ingesting something blue then vomiting blood. This seems to suggest that someone (or perhaps someones) will die from Blue Sky.
After going full-Heisenberg on everyone including Skyler and Jr, it is revealed that he has figured out a way (prob thru Grey Matter) to get some of his ill-gotten gains to little Holly.
Miss a few episodes?
Posted before I got fully caught up.
Damn. Again, damn.