I'm not an US citizen, so my knowledge of US politics may not be deep enough to grasp some of the subleties of the topic, but my overall impression was that unless you are very rich, it is in your best interest - and thus clever - to be liberal.

It's weird how often people express this idea.

Since the marginal effect of your political affiliation upon the policies of a nation of 300 Million people is trivial, we shouldn't really expect it to be "in your interest" to vote for the bloc that promises you income transfers/lower taxes, etc. Rather, it is "clever" for people to vote their affiliations (i.e. what their family, friends, and coworkers vote for). This model actually correlates with the way people actually vote.