Perhaps freakishly, I love regular expressions. I use them all the time. They literally give me godlike power over text. I find it hard to believe that there are developers out there that don't know what they are, much less that there are developers that can't use them.
They are so useful for more than development though. Anyone that needs to deal with large amounts of text could benefit so much from them. I've helped myself and other people to do hours, days, weeks, months, years, decades, centuries, and even millenia worth of work through regular expressions. (Imagine a human can process/organize 1 line of text in 10 seconds, and then imagine 100 GB of data. 1 line is about 80 characters and you get a bit over 2,000 years worth of work.)
Now, I'm sure a lot of people here have never heard of them, and some use them daily. I'm sure that some people would never have a use, while others that have never heard of them could easily find numerous uses for them to help save time.
My wife doesn't know regular expressions, but I recently helped her out with some work where I used them. It all took me a couple hours, but would have taken her days or more to do.
The uses for Excel jockeys are endless.
Anyways, just looking to see what people think about them.
Now, depending on a few factors...