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@EdwardZ
If 24 is, in your mind, reliable for a recreational rider may I suggest then for the more "advanced rider" of good taste and a whole heap: 12 spokes. A number of races have been won on Campa's 12 spoked boutique wheels so a careful builder should be able to do better.. 10 spokes, anyone?
Call it "conservatism" or not a good reciever of marketing wisdom but.... being tained by science and engineering I think looking at the results of models and testing is--- in addition to field experience--- of merit. Here its been found that the impact of spoke count on bicycle aerodynamics--- its a bicycle+rider that is of interest and not a lone wheel--- is not great as was held in the 1960s and 1970s when these were considered the "special weapons" of speed. Just as we found many of the "aerodynamic" bicycle parts--- oh so popular in the 1980s--- were without tangible merit beyond placebo effects, ultra-low spoke count wheels (not unlike the "Drillium" fashion of the day) do provide safety issues. I've been out of the testing loop for a few years now but when we tested wheels we found that rim, hub, fork, seat-tube and chainstrays were of higher order significance.
So how much energy is saved by selecting something like CX-Rays over standard spokes? Have less spokes? The question is: at what speed? At speeds of 50 kmh reducing spoke count and using different shapes of spokes can amount to several watts-- spoke shape alone can amount to as much as 1 watt. At 30 kmh it is a lot less, typically (using the same rim and hub design) under 5 watts at the extreme--- and often just 1-2 watts. Alone changing ones own position on a bicycle @30 kph can amount to as much as 50 watts (hands on handlebar tops versus optimized aerodynamic position). By subtile changes in position even on the drops one can measure as much as 10 watts difference @30 kmh. At 50 kmh (where it really matters) the differences are significantly greater. Position is, of course, a bit complicated since one needs to find an optimum between aerodynamics, power and efficiency. Its also complicated by the observation that the greatest aerodynamic and strategic benefit is to "suck someones wheels". The advantage of drafting is ENORMOUS. Interestingly the effect of wind resistance in the pack is different than being at the head--- wheels and frame interaction become more and rider position less important.