i would say the first one that *really* felt great was when both DH and i decluttered--got rid of--all of our high school, college, and graduate school books, papers, and whatever other clutter from that we had.
it was as if a lot of emotional baggage from that time was released with all of the recycled books, papers, and whatever else. it was *so* liberating.
and right now, we feel incredibly abundant and blessed. we currently own 23 boxes of books, two boxes of kitchen supplies, and one chair--all in storage--and 12 bags of our necessities (clothes, son's toys and instruments, computers). we sold our house, all of our furniture, and we will sell our car too before we leave for New Zealand.
while we know that we will be picking up possessions as we move forward (we'll eventually buy a house, perhaps a car, and of course furnish that house), what we also know is that each purchase will be a mindful, specific purchase.
we started the process of only buying what we really wanted about 2-3 years ago. we found that we really wanted high quality items that would last, and so we would pick what we wanted, save up to pay cash, and then take good care of that item. what we noticed is that things like clothing (though we do need to replace some of it currently) tends to last 5 or more years. The higher the quality, the longer it lasts, the better the value. it simplifies everything for us.
so right now, we feel *incredibly* abundant in our lives, even though we possess very little right now. we are staying with friends (who are graciously letting us stay for free), and we will be house sitting once we get to NZ (at least for a time--which is also free housing).
we will figure out how much things cost (food budgeting, etc), and then we will carefully purchase what we need when we know what we can afford.
it's been a powerful experience, letting go of everything.