Really hard to judge because the BB house is so unpredictable... But yeah - I think the 'floaters' are the ones to watch. But at least James has recognised this, and is trying to take down Chicken George (I had visions of him reaching the final weeks - noone wants to waste a week taking him out).
I'd really hate to see someone like Erika worm her way to the final four, but I think it's very likely. She does nothing, is too afraid to do anything to shake up the game, and just skates along quietly without making any waves.
Jase's strategy is quite similar, but I think we'll see a bit more of 'psycho' Jase emerge as we go on, so he may start to piss people off. And also - I think he's perceived as being a bigger threat than Erika is. So she'll probably slip under the radar more than he will.
James is another one to watch out for. He's playing both sides quite nicely at the moment.