I'd just look at picking up a used block. I don't think at this point you'd want to spend a lot extra for a few degrees. Unless you can find one that supports socket A and your future plans. I only keep up with gpu blocks nowadays, and a little at that.
I had a maze3 that is obviously not the best, but people like myself probably have blocks like them lying around for cheap. I never bothered selling mine because it probably wouldn't fetch me much. Others may have felt the same. A WTB would definitely score you one or give me a holla.
Lol.. you were already looking for used. Decent advice in there anyways. I mean best would be something from Cathar. I'd just pick up some maze or something for cheap.
both of swiftech's current blocks support socket A (s462) as well as current standards like s775, s939 and s754. the stock retention hardware supports them all.
i would look for a used/clearance MCW600x block with s462 retention hardware if you want cheap, storm if you want something that will last for the forseeable future.