For hair and nails, supplement with Biotin and essential fatty acids.

"I realize that it's no big deal to take more than your Daily recommendation of vitamins since your body just flushes it out. "

ahhhh no someone totally misled you :( it IS a big deal to take a lot of vitamins for multiple reasons. only water soluble vitamins get 'flushed out'---fat soluble vitamins like A,D, E and K are stored and can cause toxicity.
Also, excessive amounts of vitamins can chelate other important minerals or inhibit their absorption. For example, excess Fe will block Zinc absorption, weakening your immune system. this woman at my pharmacy even got an arrhythmia because she ate too many viactiv calcium chews. Everything has a special balance; too much of anything is a bad idea. So basically, i would stick with a healthy diet, and if that doesn't provide the requisite nutrients, then i would try supplementation with 1 vitamin only.

This is probably off-topic. But last I checked Centrum has gelatin in it unfortunatley. I usualy make a trip to GNC and get their one-a-day vitamin which I actually find better than Centrum anyways. www.centrum.com