I think the two people that I have changed my mind about most are Adele and Alex.
Adele, (on the basis that everyone is playing a game, that being that every person will be trying to make themselves as popular with the other housemates and with the public, virtually by any means possible) was playing the game well, I thought, until she started to use Jade. I think she made a big mistake there, because Jade is a loose cannon. This brought her gameplan to an abrupt halt as other housemates because aware of it. I felt that towards the end, she played the game too obviously, whereas originally, I thought she stood a good chance of winning.
The way Alex plays the game has never really been obvious, and on the whole I think that people who are not obvious about the way they play are more likely to succeed. But, although I don't find myself being a particular fan or otherwise of any housemates, I have actually seen sides to him that I find rather difficult. The orange saga was one, when Kate cried, he smiled. Also, when they all hid from Jade the night before last, he totally threw the joke away in the way he spoke to Jade, causing her to walk away. I don't think he expresses himself well, perhaps that's why he was quite admiring of the way Adele put things.
All the other housemates I have had pretty consistent views on, sometimes they get on my nerves, sometimes they don't. Except Tim, I just keep finding myself asking "why is he there, had he never seen Big Brother before?" If the poor guy really thought he was going to experience x weeks of intelligent and stimulating conversation, he must be living in a different world!