While I can't say nowdothis.com is the most useful website I've ever used, it's another super-simple and potentially useful site in the vein of icantdeci.de and muxtape.
I'm seeing a trend here, and i like it. Do one thing, very simply, and do it right.
UPDATE 7/28/08 I'll continue to add new ones as they come along like:
Blog of peter centofante: father, husband, brother, UX designer, freelance graphic designer, believer, realist and thinker (at least i'd like to think so.) This blog is a collection of my thoughts and things i find interesting.
I believe that ideas can change things. I think that when people are inspired by something, they rarely attempt to copy it, rather they use that spark towards their own goals, projects, and worldviews. In light of this, my goal is to share many ideas, in the hopes of making everything better.