With all the buzz surrounding netbooks, it seems as if they’ve been around forever. In reality, though, they’re youngsters in the great scheme of things. As such, their characteristics are still in flux, their makers still casting about for the best mix of form and power. Acer, with the introduction of its Aspire One AO751h model, is advancing the netbook closer to that best mix. The unit, which sells in the $350-$550 price range, depending on the configuration of its memory, processor and battery, pleasantly addresses two nagging problems with netbooks.