Dopplr, Fire Eagle (does Fire Eagle count as a startup?) and Tumblr
definitely tumblr
Octopart and Bountii are done really well.
I like the idea of Songza, but I expected a much better looking design from Humanized.
I had never heard of Songza. I just tried it out and it's pretty amazing. I agree with the red being a poor choice for a background, but everything else I think is pretty spot on.
Searching while listening to music is great, I like it.