I have no doubt in my mind that it's, at the least, a 50/50 chance that Walt will die. His dealings with Declan, the Czech Republic, Lydia, and Todd/his Uncle/his whole gang are some of what could be his downfall. And I'm only being one-sided as far as his current "business dealings" go. If you look at the whole picture, he's really got nobody left now to vouch for him (unless it's under duress perhaps) except for his children, and until Hank spills what he knows on her, Marie. So from there as well, Walt getting killed or arrested is definitely in the cards. If he survives though, I believe that it's gonna culminate in one of two ways:
1. He does, indeed, go to Prison. And given all he's done, and all that can be brought against him, there is no way in 10 lifetimes he would ever be released. Even Saul in all of his cunningness couldn't save him.
2. He avoids prison by some twist of fate, or luck, but he's on the run, alone, and/or everybody around him is compromised in some way. Be it prison, be it death, be it having to leave town themselves.
At the very least, I know in my soul this is how it's gonna end up happening. There's no way he doesn't have at least one of these things happening to him by the end. If it ends happily, this long ride will be akin to sailing on the Titanic. Everybody's having fun, enjoying themselves, then they hit the iceburg. Same thing if they leave it open-ended for whatever reason. If they don't have a movie planned for 2014, or if it doesn't wrap itself up on the Saul spin-off, that would be the stupidest thing they could possibly do. And I don't see V.G. doing that.
Staying with the topic, however, as far as the fate of everyone else, I could see Hank dying. I definitely see some of Walt's associates dying. His family could die, but they're 50/50 as well. It's all so up in the air now for me to really harbor a good guess...