Check out the new creation of Athenae, Holden, Tena and Pie, regular commentors and guest bloggers at Atrios's Eschaton. Seems like a good start, registration required unless you don't mind posting anonymously.
This might be a good spot to post some of your favorite out-of-the-way blogs and sites. I've been a regular reader of Eschaton for a couple of years. I found Billmon's Whiskey Bar via Eschaton, and Richard Cranium via Billmon's, who then reciprocated and found me. We might also look at the systemic nature of blogs and sites. Family trees. The offspring thing seems to be in the air now, or I'm simply noticing it more. Since Billmon stopped taking comments two sites have cropped up to take up the slack... Whiskey Annex, and the more studious and serious, Billmon-focused Moon of Alabama. Each and all are struggling with a new landscape, and doing a superlative job of it ... but, I suspect we can't really recreate the same synergy from one blog or forum to another. And wishing will not make it so. I hope they all find sparks similar to the places from whence they began, and I love the energy and creativity of each effort.