I think the final 3 would be:
1. Reichen and Chip (they're smart plus physically strong)
2. Kelly and Jon (very competitive)
3. Jon and Al (very funny but a lot of strategies in their mind)
I dun think David and Jeff would make it to the final 3 although they pose a threat to the others team (mainly physical). I have a sense that they might make a lot of mistakes and be eliminated in the forthcoming episodes. While Millie (the mole) and Chuck, they're great and awesome, but still, some kind of feeling tell me that they will not going to make it in the final 3.
Still, REICHEN AND CHIP is my favourite to win!