Can I Wear Jeans to Work?

I work at an engineering firm in San Francisco. I work in the marketing department. The "unwritten" wardrobe culture is very casual. I work with mostly men who wear khakis and plaid shirts. The very few women who work here dress in very varying styles. It would probably be ok for me to wear jeans, but should I? Do you think it's appropriate to wear jeans to work?

What do the people at the level above you wear? If someone at the job level you aspire to wears jeans, then it's okay (I love wearing jeans to work and did it all the time whenever the company I worked allowed it)If you see these folks wearing jeans, then it's fine. If you don't, then I would avoid it.

I work for mostly men, except for one woman, who sometimes wears black jeans. The men wear khakis. What do you think?

In that case, I would avoid jeans. You'll be taken more seriously if you don't wear them in this environment, I think. Bummer, though. I love working in jeans.