I began with zero familiarity with the case.

1. Knox: 8%
2. Sollecito: 10%
3. Guede: 95%
4. Agree with komponisto: 80%

Rationale for considering Sollecito more likely than Knox: They're linked quite closely here, but there's enough confusion surrounding the case that I can't take that completely for granted. That being the case, it's unlikely-but-possible that one of Knox or Sollecito was directly involved while the other wasn't, and my prior for a male committing a violent rape/murder is a lot higher than for a female.

Guede is clearly guilty. He fled town immediately after the murder. His DNA was found in the victim's body, by far the most difficult-to-contaminate piece of DNA evidence in the case, making it extremely likely he's the rapist. Very low prior on a rape/murder being committed by separate parties.

The inconsistencies in Knox and Sollecito's stories are definitely worth paying attention to. But there are several factors diluting their importance:

• I already had a reasonably high prior on the prevalence of brutality and corruption in Italian police forces. This doesn't leave me with much faith in their competence, especially when it comes to interrogations.
• It's known that Knox and Sollecito were intoxicated with alcohol and marijuana at the time. I don't know how many of you have ever been thoroughly trashed on this duo (I'm guessing the number is disproportionately low here), but memories formed under such circumstances are very fragile. I've personally experienced disagreements provoked by divergent recollections of events that had transpired an hour previously. Given that sort of influence, I know I would have a damn hard time reconstructing a coherent narrative of the night's events after the brutal murder of my roommate and several days of interrogation by Italian police.

The DNA evidence against Knox and Sollecito is also worth paying attention to, and is in fact the primary reason my estimate on their guilt is as high as it is. However, this is partially mitigated by a glaring problem with the case: Most of the evidence was collected before Guede was a suspect. If Guede had been identified from the start, the Knox-Sollecito hypothesis may not have been quite so "privileged". IIRC, the DNA of four unidentified individuals was also found on the knife. Plus the doubt wrt the knife matching the wounds. Plus the odds that Sollecito would take a murder weapon back to his apartment and put it away. My generally unfavorable prior wrt Italy's justice system also adds a fair amount of room for uncertainty here.

The fact that Guede wasn't initially identified also provides the police with a mild motive for contaminating the evidence. It's unlikely that such an action would be detected. That said, my prior for this sort of action is pretty low.

Finally, we come to the elephant in the case: The hypothesis that the murder was committed by three people working together, as the result of a sex game gone bad. This reads like a parody of a flailing prosecutor. Contrast prior with that for a "normal" rape/murder... ouch. And it just so happens that the one party implicated by actual, solid evidence is the one party who fled after the crime.

The rationale for my 80% chance of agreement with komponisto is mostly based on "metagaming" his position. He admits to having a "rather strong" opinion on the case, and it seems much, much harder to form a strong opinion in favor of guilt as opposed to innocence in this case. My estimate would be higher, but given how asymmetrical this case appears to me, I can't rule out "initial counterintuitiveness" and/or extra evidence as a possible motivation for posting this in the first place.

I'll read the other comments and post my update later today.