Derek Powazek has some pretty good advice on how to use Twitter like a reasonable person. Gina Trapani likes to follow everyone important (to be polite), but only actually reads tweets from a scant 9% of those people who are actually interesting.
I’ve tried this method before, but I don’t like it. It’s a hassle to maintain, and it just doesn’t feel “right”. The bottom line is that Twitter isn’t Facebook. Don’t follow people on Twitter because they’re your friends; follow them because they say things that interest you. If you don’t want to read what they’re saying, don’t follow them. If I’m following you on twitter it’s because I enjoy your posts; that’s it.