Now so famous that Lance Armstrong hunts him down, The Bike Snob blog is worth a read, ‘specially if in NYC.
The Bike Snob—profiled in the New York times (though he hides his anonymous profile)—is a wonderful examples of rule-number-one of blogging, or what used to be called writing. Write what you think. Damn your audience, or advertisers—hew to your own integrity, first. Then, folks will trust you, read you (obsessively), and all success will arise therefrom.