I would say that the primary change in Iran after the 1979 revolution was the changed relationship with the West. The Ayatollah did a great job of demonizing the West to the point where nearly every Western nation had little problem pointing to Iran as the hotbed of fomenting Islamic fundamentalism. The perception of Iran as being a nation that loathed the West and blamed Western decadence for the moral abyss that a strict and orthodox interpretation of Islam could cure was something that transpired as a result fo the 1979 revolution. As opposed to being an ally of the West and a nation that can be pro- Western interests, Iran fundamentally changed as one that was seen with antipathy by the West. Actions taken by the ruling regime in Iran made this also quite easy. The perceived subjugation of women as well as the repression of dissenting voice along with actions such as the fatwa against Salman Rushdie are all examples of how the relationship with and towards the West were fundamentally changed after 1979. This is something that is still present to an extent today in describing President Ahmadinejad's relationship with the Western nations in the modern setting. The articulation of a nation so defined against the West in political, social, and spiritual dimensions might have been one of the lasting changes in post 1979 Iran.
To me, there were a couple different kinds of changes that came about after the revolution.
First, there were social changes. Before the revolution, Iran was a very secular and open country. After the revolution, it became much more of a theocracy. Unlike before the revolution, there are now morality police that enforce the religiously based rules imposed by the government. On the other hand, it is generally said that wealth and education and such are spread more evenly than they had been.
Second, there were changes in Iran's international attitudes. Under the Shah, Iran was a US client. Since then, Iran has become more and more set on opposing the US and the West. The current issues over their nuclear program is a clear example of this.