[summitflier]

You'll also need a proportioning valve.
As far as I know there is only one size if you go stock oem gm.
You'll need the calipers to go with the disc's.
You'll need disc brake spindles.

If you don't care about stock OEM, it seems wilwood owns about 90%
of the aftermarket. You can get several different sizes, but if you go large,
you'll have to have bigger wheels.

If you're planning on doing the rear also, it requires yet a different master cylinder.
(different size wells). Also the rear disc's require a different emergency/parking brake cable setup.

I was able to save a lot of my original drum brake lines, but the connecters to the calipers are different. (In my case, banjo style).

I assume you have a fairly stock engine setup. If you have a radical cam street/strip type engine, you have to make sure you have enough vacuum for the booster.