What can I say, I love Michael Arrington's TechCrunch blog, and I highly recommend subscribing to it. I'm a little behind on my reading and am just now going through about 30 posts. It takes a while because I end up checking out a lot of the products he mentions.
Michael has posted a list called "Web 2.0 Companies I Couldn't Live Without" and you should check it out. :) Of the ones he's listed, I definitely could not live without Bloglines. I use Feedburner but started so recently that I do not really know how useful it is for me yet. Plus, my blog isn't nearly as popular as his is and very few people are subscribing to my feed.
As a result of this post, I am now checking out Pandora. I love it so far but I've only listened to three songs. You don't have to register to use it, but I assume if you want it to save your list'o'favorite songs, you have to. It's free but has ads. You can also opt for an ad-free paid version. I've been trying Yahoo! LaunchCast for a bit, but it drives me nuts that it doesn't work in Firefox (please please please stop forcing me to use IE!). Plus, they seem to play the songs in groups. If you like country, alternative, soft rock, whatever, it will play the country, then the alternative, then the soft rock for the most part. But it is a nice customizable streaming radio service that saves your preferences.
A side note: If you are interested in seeing the many feeds I read, check out the link in the righthand column that says Kat's Bloglines Feeds.