I'd shoot for a midrange helmet, like the Bell Vortex, Icon Alliance, etc, which have the features you want (removable liner, good ventilation, quick swap visors) but aren't stupid expensive. More expensive helmets aren't any "safer" than dirty cheap ones, as long as they are both rated the same. You just pay for features, designs, and the brand. Oh, and noise protection.. but I use ear plugs for that