There is another important factor when storing hops, and that's storage [u:3ybp0iaa]stability[/u:3ybp0iaa]. What this means is that as you freeze, thaw and then refreeze hops you cause them to break down. Cascade are notorious for this and growers treat them with kid gloves when sending them to storage.
If possible don't take your bag of hops out of the freezer when you need some. Instead leave the bag in the freezer and break off what you need.