My opinion follows Shelleys, get your vitamins from your food (or natural food sources like B vits from yeast derived products), but with minerals you can have very good supplementation (brands like Solaray, Solgar etc) because they can be quite hard to get in your diet depending on symptoms / history / calorific intake.
It all very very much depends on your circumstances (as mentioned with anti-biotics!) and what you're trying to do. Eg. if you're a vegetarian you may need to supplement B12 and iron for example, if you dont eat dairy / eggs you may need a calcium supplement.
My rule is vitamins from your food (with exceptions) but minerals can be supplemented (in the correct way, understand mineral interactions etc). juicing is fantastic according to tolerances and knowing how to consume them (carrots with some form of fat, adding spices to juices to heat them to aid digestion). Be sure you watch your body and dont oversupplement, most things are NOT safe for long term supplementation!
I dont see cod liver oil / wheat germ oil as supplements, really. They're staples in my diet according to time of year and nutritional intake.