I'm not addressing the question of big names - but here's my collection, to date, of my favorite sculptors (under the age of 65):
It's a miserably small collection -- since finding these people is such a hit-or-miss affair -- and hopefully, when I go through this thread more carefully, I'll find some new names to add.
One thing to remember is that there is plenty to be found outside the U.S. -- especially in Russia and the former Soviet republics.
Here's an interesting Russian site that I just found. There's over 300 items -- in no particular order -- and many of them look terrible (to me) -- but some of them are successful sculptors -- and some of them I really enjoy.