From what i've seen the only people yelling or motivating in the huddle, or anywhere else on the field, are Maloney and Luck. Lucky would be my choice ( his time left at this club not taken into account ) as he is a senior figure ( respect your elders ) and leads by example better than anyone else I can think of. 2 awesome examples 1: vs manly 2010-half his leg opened up but all he could think of was getting back in the D line to make another try saving tackle 2: vs tigers 4 days ago-damage was obvious the moment he was tackled yet he made 3 more tackles hopping on one leg because we were under attack! The guy is a freak! He has my absolute respect and admiration. He also seems to have a slightly better relationship with the ref's ( might be an Aussie thing? )
..more I think about it, the more I think Maloney. Luck is probably the obvious choice and he probably deserves it but I feel like the captaincy could only add to Maloneys game. The only argument so far is hes a bit hot headed with the refs, but as captain he would be allowed a bit of leeway in that regard. Hes in a position to lead the team and is already one of very few members who are prepared to speak up in front of the team in these team huddles. Maloney and Luck do all the talking, they are the options we have.
The only problem with that is I don't think Maloney has the respect of his teammates, not enough to be a captain anyway. Judging from what I've heard round the traps, most think he's a right pain in the arse. Not a bad chap by any stretch, but one of those guys who just won't keep their mouth shout. It's a good attribute to have as a half, but as a captain it's not in the amount of words you say but the quality.
Lucky, Simon, and even Hohaia, Rapira and Ropati to a lesser extent all say less but when they do speak people sit up and listen.
The other thing is Jimmy is still green in the NRL, especially for a half, and has many areas of his game to work on before he can even start considering a leadership role.