What is everyone running in their systems? So many choices out there, just wanting to hear what you all have experienced. I am doing the power stop front brake upgrade with the red calipers. I am putting the summit racing drilled and slotted rear rotors and power stop pads. All brake hoses are being replaced with the Russell kit #692370. This is all going on a 1991 Z28 5.7. I will be mostly using this as a street car but will be taking to the track as well. Thanks

Look at the boiling point on the bottle I use Prestone DOT 4 http://prestone.com/products?detail=AS800Y
But all brake fluid absorbs water so the key here is to change it and bleed the brakes at least once a year.

If you still have the stock 10.5 discs you will overheat them even with drilled a slotted rotors on any track that has turns that require you to use the brakes much.
If you do run into fading issues look into LS1 front (C5's are pretty much the same both are 12" 2 piston) and are really cheap.
I use Brakemotive (the E-Bay store for Powerstop). I have LS'1 all the way around a new set of pads and rotors is lass than $200 and I just replace them every year.
The car sees about 3-4 track days a year on the 2 mile 11 turn course and a couple of Thousand street miles.
A note on drilled rotors I have had 1 rotor crack in the last 3-4 years so keep an eye on that...