Well, since you can get Lichborne, for fear breaking, and you are Unholy (So you have Death's Advance and don't need snare reduction) I'd most likely go kill lots of stuff, and hope that the Reverberating Shadowspirit Diamond pattern drops for you.
I spent a good while yesterday cruising the top DKs in the arena world and found that there really is no consensus on what is best. It is all a matter of preference really. See a lot of 1% spell reflects and yes, there are some using the new meta. Most Orcs tend to go with the 10% stun, but now that IBT breaks stuns idk about that. New meta is obviously far superior in terms of damage, so if you are cool with your survivability I would farm that or just pick one up now that they have dropped a ton in price.
I would recommend just trying to find one that will make you gold and buy whatever meta gem you want.