Rans Enduro Sport, Hase Kettweisel Tandem, Merin Bear Valley beater bike
Depends on the rest of the bike. Most bikes have the brake cable run down the left side of the top tube. A 90 degree noodle works best with them. If the brake cable happens to run down the right side, the 130 degree noodle generally seems to line up more perfectly.
American Breezer mtb, American Classic ti road bike w/SRAM Force and XO, Crotch Rocket, SOMA 69'er w/XX-1 mtb, Handsome Shop Bike w/700c wheels. Bianchi SS 'cross
Used properly, the various bends (And, if you're careful, you can customize the bends) allow you to keep the housing close to the frame (Rear brake) or head tube (Front brake) for a cleaner look and to minimize the potential for the housing/noodle to snag on something.