I'm in the "minimal supplements" camp. The key to a good raw diet is to feed about 70-80% meat, 10-20% edible bone, and 5-10% organs (yeah, I know, fuzzy math there, but it's just to give you an idea). About half of the organs should be liver and the other half can be whatever "squidgy" organs you have access to (kidney is a commonly found one, spleen is also good, but keep in mind that heart is considered a muscle meat for doggie feeding purposes).
I also think a good raw diet should have at least 3 different proteins given on a regular basis, unless of course your dog has serious allergy issues that require you to really limit protein choices. If you can do all of those then I would only supplement with fish oil for the Omega-3s. Plus of course any supplements required for the individual dog's health issues (one of mine gets glucosamine pills to support his joints in addition to the fish oil, the other gets just fish oil except during her allergy season).
I've found that a simple raw diet plan, as long as you meet the above criteria, is quite sufficient. The pet food companies have drilled it into our heads that a good pet diet is so complicated that we couldn't possible do it ourselves. We've been feeding our dogs this way for about 6 years now and have seen very positive changes.