I may be talking outta my ass, but ISIS, octalink 2, the new DA/Ultegra/105 w. the integrated spindle are probably better technology (i.e. lighter, stiffer, more durable) than ANY square taper crank.

Still too new to be 100%, but keirin racers and fixed dudes are the only ones who haven't gone over to the other side.

Kinda like aheadset, square taper gets by on style. That said, lots of cranks are sweet. C-record are just the prettiest. And I don't think crank stiffness makes much of a difference unless you're a clydesdale.