It would depend on the circumstances of your death and the type of item or items (You could create an entire set of gear as well, though each item independently would be weaker than say, just ONE item, however it would be YOUR character's set which is cool enough in it's self).
Most commonly, another of your characters would inherit the item and while these items are very powerful it would come down to a risk vs reward situation. You could risk using it for the bonuses it gave, but you also risk losing it if it was stolen from you. These kinds of items would be pretty high profile I imagine and would be the target of people who wanted them for themselves or even just to sell it to someone else for a profit.
Say your character died and made such an artifact... Over the next 3 or 4 years of gameplay, there is no telling how many people will have possessed and used the item or where it will end up. You may even run into it again someday if you lost it years ago. But these items would be truly unique and one of a kind. If you used it wisely, you may have kept it yourself all this time. Really depends how you play and what you do I suppose.
Nothing is soulbound.