Sadly, my MAC addiction only recently began, but I noticed that there's a lot I wish I had gotten from Madame B collection--I was too late for that one!
I've loved MAC for a long time. The collections really starting getting good around 2001/2002.
I love Rebelrock and I wish I got a backup of Blue pigment because it's so pretty. I use Porcelain Pink MSF too and wish I had gotten a backup of that.