Ok, I admit, I'm a HUGE Quantum Leap fan (note the present tense, I haven't given up on a new series or movie). I would also "do" Dean Stockwell in a heartbeat. Ok, probably too much information, but who cares.
I was totally pissed when the series was cancelled, but that was before I had a computer and could write e-mails to everyone and bitch. I do want to thank Don Bellisario for at least putting some closure on the series with the final episode "Mirror Image", which left me bawling for days, then going "huh?"
For years I've pondered the episode, trying to figure out what exactly made me cry like a little girl (probably that whole text thing at the end that said "Dr. Beckett never came home again"), and think about what really went on in the episode.
The reason I'm writing this now is because the SciFi channel just showed "Mirror Image", I watched it, and once again, cried like a baby. I searched the internet for a site that would say for sure what had really happened, but every other fan seems as clueless as me... offering their thoughts on what happened and why.
Here's my theory:
Al died in the POW camp in Viet Nam
Dr. Beckett lost his brother in Viet Nam
Dr. Beckett builds the time machine and leaps around willy nilly. Al helps him along (because Sam changed the past, Al didn't die)
When Sam leapt into Beth's life, he was suppose to save the policeman (which he did), but wasn't suppose to tell Beth that Al was alive (because he wasn't really).
In "Mirror Mirror" Sam figures out that he's the one leaping, changing stuff all the time. He realizes (and its said several times) that the dead come back to help the living.
He leaps back and tells Beth that Al is alive, and at the very end, the audience sees the picture of Al glistening blue and "leaping" (the dead coming back to help the living).
The reason that Dr. Beckett never makes it home is because he becomes Al (that whole, "which reality do you believe, the one you see or the one in the mirror" comment that Al the bartender makes to Sam), comes home, marries Beth and has two kids... that's his "sabbatical".
That was the one thing he couldn't do for Al, because Sam thought he had to continue leaping and "making right, what once went wrong".
So, that's my spin on it. Either that, or Sam was Al all along. Who freakin knows.