When it comes down to it, Qui Gon Jinn is just the prequel version of Obi-Wan. Both are wise old mentors who guide the scrappy upstarts through the first movie in the trilogy, and both die like morons so the heroes can venture forth on their adventures without the crutch of sage wisdom. Maybe if Episode I opened with someone taking Qui-Gon's daughter it'd be more exciting, but as it is he's just Diet Kenobi. He's so vanilla that fans have had room to come up with awesome backstories for him; most notably, the one where Qui-Gon was a Sith the whole time.
Let's look at the facts that support this batshit hypothesis.
Everyone around this dude ends up a turncoat. Is he really the dumbest Jedi Master ever, or could it be that he's manipulating things behind the scenes, a la Emperor Palpatine? The Dark Side has been shown to cloud Jedi judgment, after all.
But wait, Qui-Gon has used the power of the Force Ghost. He taught Obi-Wan and Yoda from the grave. Force Ghosting is a Jedi thing, right?
But uh, I guess Qui-Gon never got the chance to show a pre-lava'd Anakin. Yoda got the Force Ghost memo after Darth Vader came to be, so unless Qui-Gon was a Sith as well, he wouldn't bother chattin' up his old grandpadawan to explain the mysteries of CGI astral projection. But we see Anakin's Force Ghost at the end of Return of the Jedi, so someone must have taught him. Unless Vader thought to research the subject on Wookiepedia, he had to have taken that page from Papa Palpatine -- which would mean that Force Ghosting isn't exclusively a Jedi ability.
At the very least, Qui-Gon is what fans have come to call a Gray Jedi; sort of like Luke Skywalker during his angsty period when he was swinging from Light to Dark. Though Qui-Gon seems to be an alright guy minute-to-minute, his beefs with the Jedi Council and his actions behind the scenes imply something more sinister. If only he could have told Darth Maul.
Pretty iconic shot, right? Luke's lifelong home is destroyed, his aunt and uncle murdered. All he's left with is fuel for his rage against the Empire. But isn't it a little weird to think that Stormtroopers did this? I get that the Empire was looking for R2-D2 and C-3PO, and that they'd be more than willing to trash someone's home to get what they want. But what they did to Luke's guardians seems a tad dramatic.
People in Star Wars get their arms chopped off, blown up in space and thrown into alien sand vaginas, but there's no one else in any of the movies who gets it worse than Owen and Beru Lars, including the asshole who gets his legs chopped off before getting his nubs dipped in piping hot magma. Seriously, a blaster couldn't do that -- their flesh is completely vaporized. I don't know anyone that ruthless. Do you?
Oh, right. According to the scenes added in the Special Editions, this dude was on Tatooine at the time of the murders. Looking at the evidence, it's completely possible that Boba Fett killed Luke's aunt and uncle. For one, we're well aware that the Empire is willing to outsource their jobs to bounty hunters.
In this classic scene, Vader is outlining the bounty stipulations for a handful of mercenaries, emphasizing the importance of capturing the heroes alive. Darth makes a point to turn and point at Boba Fett, talking down to him as though he was lecturing a toddler.
You don't point at someone and say that unless they've been caught doing it before. Boba Fett has such a rep for disintegrations that word got all the way up to the #2 seat in the Empire. Dudes like Boba Fett are the reason there are signs at multi-level grocery stores that say "NO CARTS ON THE ESCALATORS" -- you know some dickbag spilled ten pounds of kale all over the machinery before Trader Joe's started putting those warnings up. It stands to reason that the guy known for disintegrations was responsible for the most prominent disintegrations in the original trilogy.
But maybe Boba Fett wouldn't have been around to immolate Owen and Beru if Obi-Wan hadn't chosen the worst possible planet to hide Darth Vader's son. Then again, maybe it was the last place anyone would look...