Yokozuna Jet Lubed cables are the smoothest I have found. However, you better have a Dremel mototool, or similar, to cut them properly and they will not tolerate sharp turns coming out of the hoods if you run short reach bars.
I find the Nokon Al housing to be a real pain to install and they get creaky sounding in short order. But, they look cool.
DA and Jagwire are the easiest to install and are my favorites for low cost.
Just installed the newest Gore Ride-On Professional System shifter cables and low friction brake cables on a new build a few days ago and, after only two rides, both work really nicely. I'm not sure if the Pro System is as smooth as Yokozuna. If not, it's a close second.