I run Wilwood 4 pistons on the front of my Impala SS. I got a good deal using my car as a 'prototype', but have really started to enjoy the benefits of good brakes.
I like the Wilwood drop in pads. Remove one allen bolt and the pads drop in from the top of the caliper. Wilwood also has an extensive line of pads for many applications. I have a low dust quite pad for the street and a more aggressive pad for the track (more dust, some noise and works great when hot). The pads are pretty thick, too. I haven't wore out a set yet.
The Wilwoods really increased the amount of time I can spend on the track. At BIR (3.1 mile course), I can get an extra 3-4 laps out of the brakes (compared to stock) before I start to get the spongy feeling.
Now, for most guys, I would imagine they will never work the car to the point of worrying about brake fade and heat. Any decent caliper and rotor upgrade should be sufficient, as long as the fluid is changed regularly. Just a simple fluid flush would make a noticable difference in the resistance to fading for most people.
If you are going to upgrade, make sure to use good calipers, good rotors, good fluid and a suitable pad. The best brake setup will still suck with old crappy fluid and cheap pads.
Personally, I also avoid the crossdrilled rotors. I have witnessed too many crack when they 'connect the dots' and several have broken in pieces after a hard track run. They look good for the eye candy on the street, but most aren't up to the task of hard track use.
There is my long winded 2 cents on brake upgrades. Whew!
Randy