Technorati has their top 100 blogs, with popularity based on the number of links to the blog. These popular blogs are high volume and tend to be heavy on geek-tech subjects, though a number of political blogs are also featured.
These blogs are linked to because the content tends to be pretty good, but the busy blogger may not have time to follow these feeds effectively. If you blog about a niche topic, you've probably been scooped by some of your friends who caught a mention of your favorite subject on BoingBoing or engadget.
I've created a handy, subject-filtering tool just for you. Enter the keywords you're interested in and you'll have your own, custom RSS feed that search for those keywords from many of the most popular, English-language blogs. Subscribe to that feed and you've narrowed your view of these high volume blogs to just the topics you're interested in.
For example, I blog about bicycling. I watch for the terms bike, cyclist and bicycl. With these words, I get bikes, bikers, bicyclist, bicycling and so forth. I tried "cycle" at first, but I got a lot of posts about recycling, budget cycles, and the water cycle. You may need to experiment similary.
Let me know if you find this tool helpful. I've created it with Yahoo Pipes; if you need more than four keywords or you need some flexibility in where the searches are done, it's not difficult to copy my Pipe and create your own.
Try out the user provide keyword search for top blogs tool.