My favorites are probably Henry Hatsworth (monocle = win), Starmony (such great quality for a free item even though I never use it)... I can't think of any others off the top of my head.
My least favorite is probably the Sour Patch kids items.
How about for a free item theme I'm tired of? Skittles. >.> Some of the items are neat but I am so tired of seeing them.