I think the bigger bang would be in the kind of hub you have. The less dish the better, which starts to conflict with the latest designs out there. My M15 White hubs are pretty extreme. I'm building out some MA2 36 hole rims I have, and I am currently thinking of the Riv/Phil freewheel hubs, since I come from the freewheel generation, and the cassette hub advantage doesn't get me all excited, plus the spoke angles should be better.

The main advantage to the Phil was when Shimano had axle problems with their freewheel hubs. Having addressed that with cassette hubs, the current problem area is the cassette shell. Phil has addressed that, but the hubs are pretty heavy. Whites are cheaper and lighter, and have the Ti shells. You can also get better hubs from DT which uses the superior loose bearing model, but in a super hub, or there are Chris King hubs, which come from a great headset company.

Myself, I haven't even managed to break an LX freehub, which sorta sucks to the extent that I could then righteously stomp off and buy one of these super hubs for a real reason. At the moment, they are just nicer parts, not so far necessary. And in my case I was riding at near tandem loads on 700c...