I prefer cotton thread in a color that matches the undercollar. I use Mettler threads--either 50 or 60.
There are two types of basting threads: unfinished which generally comes on skeins but also in spools in Europe and thread with a starched finished which is on spools. The latter, but not the former, would be ok.
A disadvantage of cotton thread is when it dries out, it will break. Old threads can often be resusitate by soaking them in water. Most garments are not worn that many years for this to be a problem unless you live in a hot, dry climate.
If you are a good pad-stitcher, you can use any color cotton thread. This is a good time to empty your bobbins of colors you won't use again. This is a bigger problem for womens' jackets than mens.