We used to collect them
The larger sets are stored in their original boxes, the smaller ones in zip locks - and I have a bunch of the Paradisa ("lego for girls" - pinks and pastels) sets that I may be selling soon.
Oh wait.. the kids lego is what you're asking about, not *ours*
We've got tubs right now... the primo I sent off when they outgrew it (the baby lego).. we've got a tub of animal Duplo sets, a tub of town type Duplo sets (including bob the builder and circus stuff).. we've got a random box downstairs, plus a winnie the pooh set that is in it's original box for some reason
They've got a couple tubs of the smaller lego pieces too for when they're a little older.