Index: trunk/src/org/openstreetmap/josm/data/Preferences.java
===================================================================
--- trunk/src/org/openstreetmap/josm/data/Preferences.java	(revision 469)
+++ trunk/src/org/openstreetmap/josm/data/Preferences.java	(revision 470)
@@ -209,4 +209,9 @@
 		properties.put("propertiesdialog.visible", "true");
 		properties.put("osm-server.url", "http://www.openstreetmap.org/api");
+		if (System.getProperty("os.name").toUpperCase().indexOf("WINDOWS") == -1) {
+			properties.put("laf", "javax.swing.plaf.metal.MetalLookAndFeel");
+		} else {
+			properties.put("laf", "javax.swing.plaf.windows.WindowsLookAndFeel");
+		}
 		save();
 	}