When it comes to daily "roundups" of politically-oriented news and commentary, I like to think that I publish the best of them. For a more concentrated, weekly roundup, however, I highly recommend Ender's Review of the Web.
Comparison: Rational Review News Digest excerpts and links to anywhere from 25-40 political commentaries a day, or 125 to 200 a week. Ender's Review excerpts and links to 40 or so per week. It's not really a matter of quality versus quantity; over at RRND, we try to be firstest with the mostest, including the most interesting (in our judgment). Tom Ender chooses to be weekly with just the most interesting (in his).
Check it out.