Ever since we saw a glimpse of the backyard construction last night, it's been sort of assumed that the show will go off their usual format and have a rare week three endurance round. The contestants seem to believe this, too, and have sort of been preparing for such an event.
So who is going to win? Here's what I think will happen IF it's a hanging or "hold on to your key" event. Anything besides that would cause me to reevaluate my order.
From first eliminated to victor:
1. Lane. He's just too bulky, and these contests tend to favor lighter people.
2. Kathy. She's shown no athletic ability, and has had to go a full day without a smoke. She'll slip up, and be disqualified.
3. Enzo. Many of the same problems as Lane, plus I don't think he gives a damn.
4. Britney. Her problem isn't going to be the physical capabilities needed to make it. She could easily win such a comp if she set her mind to it. But she's clearly been pampered all her life, and will start whining pretty early on. Her dismissal will be full of drama and tears, and probably an "injury" that won't be as severe as she believes.
5. Hayden. After Britney leaves the contest, the rest of the cast will carry on for quite some time. Hayden will eventually drop once he discovers that both Kristen and Matt are willing to stick it out for as long as possible.
6. Brendon. Knowing that most people are gunning after at least one of the coupled chemists, he'll do everything he can to stay in the game. It won't be enough, though, as he'll struggle for quite some time before dropping (or letting go of the key, depending on the game).
Here's where it gets dicey. Either Matt or Kristen could probably endure the competition for as long as it needed to go, but if I had to pick one to outlast the other I'd probably go with Matt. Given his aggressive gameplay strategy, though, I bet that he'll just want to ensure his own safety and allow Kristen to become HOH. After a few minutes of whispering, Matt will drop/let go/walk away/whatever and give Kristen the victory.
So my shocking prediction is Kristen.
Edit: I forgot about Andrew, which isn't hard to do. No big deal, as he'll be out around the same time as Kathy and Enzo.