I have heard that the Avid Ti Brake arms are pretty flexy :(
I would reccommend;
XTR Brake Arms
XTR Brake Lever
I have heard nothing but praise for XTR series of components. The only downside WAS the price, but that has now gone down drastically, making them a brilliant choice.
On the side of cables, I have heard that the BEST cable, for everything is;
Odyssey Linear Slic Cable
This setup is not only light, but (relatively) cheap, strong, and super powerful braking!
The heatsink V pads are also a good choice