Between 2005 and 2012 the finder icon in my dock (OS 10.4.11 ppc) looked sharp but of late it's been looking vague. Then recently my Safari (not the latest security update) was behaving weirdly, and during that time lo and behold the icon was looking sharp again?!? Would love to add small sized screenhots to explain. For lack, it's this icon: http://s.macgasm.net/wp-content/uploads/2011/01/Flurry-of-Mac-Apps-Updated-this-Week-17-09-2010-2.jpg
Light bulbs you shouldn't buy
There are plenty of dimmable LED light bulbs, but make sure you don't buy the ones that flicker when you dial them down.