Warren Buffett does not "want higher taxes," he realizes we need more revenue. If the federal government COMPLETELY shut down all discretionary income (shut down the military, VA, state department, Federal courts, federal prisons, currency, interstates, SEC, FBI, CIA, FDA, Customs and INS, etc, etc)... we would STILL have a deficit.
It is simple math... and he is good at math. He likes things that work... he likes when the numbers add up. Him writing a check to the federal government would NOT solve anything. He is actually wanting a solution...
Now, he has said on a number of occasions that we must cut spending... we have to stop making so many promises we can't afford, cut the military dramatically, and many forms of social spending. However, at the end of the day, we have to bring in more revenue... his point is that it makes sense for the rich to pay more than they are.
His experience as an investor and a businessman has taught him a lot about how the economy works... and how investors think. A higher tax rate on high incomes would not cause the economic devastation that many would try to convince us of... and since we have to bring in more revenue (simple math), even with all the reasonable spending cuts we can (and should) do), some taxes are going to have to go up.