Dean Esmay has a long, link-filled post on the topic of the increasingly uselessness of the Left-Right dichotomy for discussing American politics. While I’ve long thought Left-Right and Liberal-Conservative were poor expressions, especially given how their meanings have changed over time, I’ve never found anything that really works. None of the essays/polls he links get the job done, either.
I’ve argued that a circle is better than a line for discussing these things, since Left and Right actually converge at their extremes. I contend that Stalinism is the extreme Left wing and Fascism/Naziism is the extreme Right Wing, although some would disagree with that labeling.
Two axis systems, like Pournelles (linked by Dean) and many others, are typically better than one axis systems, but they tend to create problems. Why? Because most people are inconsistent. They support government regulation of some personal conduct but not others. They support some taxes but not others. Aside from the anarchists, it’s just hard to categorize most people because they don’t think about government all that much and they don’t have very well thought out views.