For many years and is still common practise on broadcast shoots, the standard white was/is the directors/reporters script. This is often fooled by using a 1/4 CTB to warm it to taste. However, one thing to be careful about is that some white papers can be a bit on the cool side. Some of the white balancing plastic found on some of the old 3/4" u-matic or Betacam VTR weather covers were variable depending on how much dirt was on it and how yellowed it had become.

Commonly I just use the pre-sets especially on the high end cameras. These cameras usually have 3200K, 4300K and usually 6300K as the built in pre-sets. The latter is more useful than 5600K because it's the common reading on an overcast day and it factors out a bit of the blue from the sky on a sunny day and looks great.

On the A1, Expodisc. On a 2hr indoor shoot in a room with beige walls lit with one key and the afternoon sun through large windows, we white balanced before every take. You must lock the cam off on the exact framing first.

Cheers.