Do what I do with my cards, IF you're more of a player than a collector.
The cards I definitely NEED for a deck I keep about 2-3 of them (Claydol, Uxie, Azelfs, etc). And I build 1 deck. If I want to build other decks, I proxy them. Seeing as you can only use 1 deck at a sanctioned tournament, I proxy most of my cards. Then when the time comes and I decide what deck I want to play, I take the proxies out, and put the real cards in. Saves a lot of money then trying to get the same card over and over and over again just because you want different decks. Which is why I'm not big on the whole "CML FOR CLAYDOL! UXIE!" lalala because I already have a few. People want the real card for EACH deck, which is very hard to do. I would say keep 3 of them, trade the other 2 for cards you need.