I have friends who have dice of every conceivable size and shape. Personally, I have:
36 x d6 (probably more like ~30 now, they tend to get lost)
2 x d10
1 x d4
1 x d8
1 x d12
1 x d20
The d6's came in a pack, as did all the rest. Obviously I'm not a D&D player, I'd probably get a couple more of each if I was.
But either way, I don't collect dice, and I don't really care about my dice. If they get to the point where they need to be re-inked, I'd buy new ones.
Of course, that's me. I know a lot of people love their dice a lot