Out of curiousity, I went to BuyBlue.Org to see Geico's political contributions. Warren Buffet is listed within the company bio but 94% of the contributions listed go to Republicans:
http://www.buyblue.org/node/981/view/summary
GEICO has found that driving down costs brings drivers by the droves into its fold. A wholly owned subsidiary of Warren Buffett's Berkshire Hathaway, GEICO has traditionally provided auto and other insurance to preferred low-risk demographic groups (such as government and military employees) but has also begun to sell to nonstandard (high-risk) drivers. In addition to auto coverage, the company's offerings include motorcycle insurance and emergency road service. GEICO eschews agents in favor of direct marketing through such vehicles as direct mail, TV, radio, and the Internet.
GEICO is a conservative organization. Contrast it with "Progressive" Insurance, which is a comsymp front.
I seem to recall an earlier thread on FR about GEICO which claimed they have a reputation for not paying out money on claims. That may be how they can charge lower rates.
A lot of their commercials have been very clever, but I find the recent ones with the lizard speaking with a British (or Australian?) accent annoying.