Brand name cables are all good. Shimano, Campagnolo, etc and many third party cable makers that have been around awhile. If you have Campy stuff, then use the cables Campy recommends for those particular shifters and brakes. If you have Shimano stuff, use Shimano's recommended cable for the particular shifter or brake you have. If you just don't trust trust them or think the difference in price is going to make you rich, then use whatever third party cable you like such as Jagwire.

You can sometimes get away with changing just the cable... if it's proper for the housing you have. But don't try to just replace the housings without also replacing the inner cable.

Be certain you understand how to adjust the components, cut the housing and other stuff you'll have to do. Shimano, Campy, SRAM all have their installation and adjustment procedures online. Some are a little harder to find.