Java SE (Java Platform, Standard Edition)

Hello!

Currently my Java Swing project is using Substance look&feel, but my application is targeted to lower end machines and I want to minimize resources while retaining a satisfactory user experience. Substance is nice-looking but it is wasteful in terms of memory consumption and has visual effects I can live without. Can somebody maybe suggest such a L&F, that looks (er, and feels, lol) pleasant enough, but minimizes resources?

I say free only because ultimately this will end up as a small-scale commercial enterprise which probably rules out some licenses.