I may be a latecomer to this particular social tool, although it’s been on my Radar for some time – but weheartit.com is a great site. I’m having trouble using it at work though, given the frequently explicit nature of the images people seem to bookmark. ffffound is a much more purely “arty” service in a similar vein.
Plus I wonder what the etiquette is with regard to hearting your own images? A touch vain perhaps, but I couldn’t help it 🙂