(FORTUNE Magazine) - Warren Buffett isn't one of those guys who always needs to have the fanciest bling on the block. This is, after all, the billionaire who loves to dine at Dairy Queen.

And his daily commute takes only five minutes. But after he saw Rick Wagoner, the chairman and CEO of General Motors (Research), on CBS's Face the Nation in early April, Buffett decided it was time to splurge for a new ride.

He faxed Wagoner a note that praised him for being "candid, composed, and rational" in his discussion of problems GM faced that weren't of his making, and added a P.S.: "I don't buy cars very often, but the next one will be a Cadillac."

Wagoner wrote back offering to help Buffett with the purchase, but it wasn't necessary. Buffett dispatched his daughter to a nearby dealer so that he could, as he put it, "cast one vote for the guy." She picked out a DTS--a sedan that is the model of choice for senior-citizen drivers and starts at $41,990. "I think I'll become a car salesman, because I would have no trouble selling this car to anyone," Buffett says. "I'm behind GM 100%." In case you were wondering, he paid cash.