I am a distress ink addict so be careful because once you have one you want them all
.
The colors you should choose really depends on what kind of projects you do. Each color family has muted colors and more vibrant ones so look at the projects you do and decided where you sit on color intensity and go from there.
As for all around "must haves" I would start with some neutrals:
*Vintage Photo (Walnut stain is great but quite intense where VP is more in the middle and i find i reach for it a bit more).
*Antique Linen (is great for adding a gentle color to stark white backgrounds without changing too much of your color scheme)
*Pumice Stone (a really nice grey to use on masculine cards)
These are colors that i really love:
Orange...Wild Honey
Pinky Purple...Victorian Velvet
Blue...Tumbled Glass
Green...Peeled Piant
Red... Barn Door(a true primary red) and Fired Brick (has a bit more brown in it)
Yellow...Mustard Seed
Just pick colors that you love and have fun with them.
There is a great YouTube video series called "No Stress Distress Inks" that is really fantastic if you are just starting out. Here is the link to the first video (i think there are 12 in all):
No-Stress Distress Inks #1 - YouTube