My favourite monthly collectable would have to be June 2006's Dark Halo
I like this for many reasons, First of all being that it has an unbelieveble gold sink which means the value of the item is always on the rise, this in effect makes it agreat investment. However at the same time as investing in it for a profit it wont be hiding away in your inventory while raising value, it would almost certainly be equipped to your avatar as you can get heaps of enjoyment out of it while you watch its value rise on the charts as it can suit almost any gaian with its unique and classy style. To be honest it looks amazing, its got a demonic look with that spark of originality which for me is a winner, and as its been around for so long its strongly recognised as a symbol of success on Gaia Online. Its become almost like Gucci or Prada in the real world, which can lead to many people buying one just to make a statement to show their wealth.
I would rate this collectible 5 stars as its got the full package and for me its a definate winner.