This is one of the few issues where I'm very militant.

Iran and NK have no right to pursue a nuclear infrastructure that is geared toward producing weapons-grade nuclear material. Period.
If Iran wants to build a nuclear power grid, a heavy water reactor will run on unenriched U235 cheaply without issue.
The French have an excellent record of managing their nuclear reactors and nearly all run on U235.

The only reason NK and Iran have thousands of centrifuges running is to produce U238 for use in a nuclear weapon.
Considering that Ahmedinejad has openly declared his nation's intent to wipe Israel off the map, the world cannot allow Iran to produce weapons grade uranium.

I'm not saying we need to invade and occupy; it's the last thing we should do. But we should take whatever steps are needed to make the pursuit of weapons-grade material prohibitively expensive -- up to and including air strikes on their centrifuges and reactors-in-construction.