There is a general assumption among most people that Iran's uranium enrichment is an attempt to build a nuclear bomb and that the stated purpose of building power plants is just a smokescreen.  However, Juan Cole believes that the Iranians really do want and need nuclear power:

Nuclear reactors lend Iran a hope of energy independence. Iran produces 3.8 million barrels per day of petroleum and uses about 2 mn. b/d itself. It is likely that soon Iran will use up all of its daily petroleum production, leaving it without the petroleum income windfall upon which its government depends.

Instead of nuclear capability, Cole believes the Iranians are seeking nuclear latency.

Latency is the possession of a nuclear energy program and of reactors, which would allow the production of an atomic bomb on short notice if an extreme danger to national autonomy reared its ugly head. Nuclear latency is sometimes called the 'Japan option,' because given its sophisticated scientific establishment and enormous economy, Japan could clearly produce a nuclear weapon on short notice if its government decided to mount a crash program.

I am not so sure, becaue Iran's leadership was exposed as the corrupt, violent, totalitarian fraud it is after the election, so it is hard for me to trust the words of Supreme Leader Khamenei when he says nuclear weapons are forbidden by Islamic laws.  Still, after Iraq, any assumptions about WMDs have to be taken with a grain of salt and Cole makes a convincing case that Iran has more to gain from latency than capability.  Between this and his list of the "ten things you think you know about Iran that probably aren't true," Cole has definitely shaken up my core beliefs about Iran.