Anything that's closer to balanced than most over-the-counter sets works for me. I'm currently doing .038 (guitar string)-.050-.065-.090-.125 tapered (Hipshot B/A) - this averages around 30 pounds per string. But I've done a set even lighter than that and a couple sets leading up to .045-.060-.080-.105-.145 tapered - in that case things average more like 42 pounds per string.
I like the feel and tonal matches better when the sets are balanced, and when all the mid and upper strings are lighter/matched-tension then the low B/A string doesn't seem flabby anymore regardless of whether the set is lighter or heavier.
Are you asking for a subjective opinion, or wanting an objective one? There's no objective opinion - but personally I like my strings to hover around 30lbs of tension, plus minus a few pounds.