There are some replacements in here for cards that I don't currently own (for example, I'd like to have additional Mindslavers or Karns in here, but don't have them).  Ideally, I'd replace the Karplusans with Burnwillows (but, again, don't have any).

Locket of Yesterdays was thrown in as something of a replacement for a Prophetic Prism that I was missing, but it's actually turned out to be a pretty sweet piece as a one-of.  Once I use a Chromatic Star or Sphere, any of the next ones I draw basically read:
"Chromatic Something - 1
T, Sacrifice this, draw a card: add 1 mana of any color to your mana pool."