1) Fermentation temp control -- are you starting to see a pattern with all the other replies? My guess is that anyone who didn't put this in their top 3 doesn't have fermentation temp control. (Part of this includes pitch temp too -- I always pitch a few degrees *below* target ferment temp.)
2) More efficient chilling -- Improves consistency of hop utilization, better cold break, etc.
3) Gelatin -- this isn't "beer quality", per se, but getting beer to clear more quickly allows me to drink it fresh and generally gets beer to its "mature" point more quickly. It's probably not actually in my top 3, but nobody else had mentioned it so I threw it in.