There are varying estimates on how much oil is in ANWR. Some credible estimates put it at the same level of oil that we import daily from Saudi Arabia and would last at that production level for many years. That's hardly an insignificant amount.

The Strategic Petroleum Reserve is only intended to last for a matter of weeks, not years. The single biggest withdrawl that I'm aware of is when Clinton authorized selling some to artificially lower gasoline prices. It was a populist move that accomplished nothing and to the best of my knowledge, the oil has not been replaced.

Conservation is important but by itself isn't likely to meet the growing energy demand for the next 30 years. It'll take a combination of conservation and increased capacity to meet our energy needs. That is exactly what the Bush Energy Plan calls for, BTW. Conservation alone can significantly slow the rate of growth in energy consumption but isn't likely to completely meet that demand without some draconian measures. Slowing the rate of growth is a good thing given the simple mathematics of exponential growth.