Please ignore this post, which makes the utterly ridiculous recommendation that customers should care about what tools developers use in their work. Programming is such an individualized task that what works for one person will not necessarily work for someone else.
That's why, when talking about tools, I like to describe why *I* like the tools and how it makes my tasks easier. I've tried a lot of different IDEs over the years, and I always come back to jedit. Some of it is definitely due to comfort, but big IDEs tend to make assumptions about how and where you organize your code, and want you to do all of your work via the IDE. I like to drop to the command line a lot, to do SVN diffs, commits, and updates. It feels faster to me, even if it isn't, plus those are the tools I have at my disposal on my server's command line – no fancy GUIs there to guide you.
If the answer is notepad++ you should stay away from that company, no matter how cool the flash design looks.
When evaluating a development shop, you're much better off asking them how they score on the Joel test. It gives you a much more complete look at "the quality of a software team." But Oscar, #9 says "Do you use the best tools money can buy?" As I read the question, its really asking if you provide them with the best tools to keep them productive and happy. If someone is a wizard with notepad++ or vim, who's to say they must use anything else?
The recent revelation that at Microsoft, the top developers prefer Old School methods highlights that fancy programming environments aren't necessarily better or make for better programmers.
"When there are five things on the screen, you can burp that out [in text]. But when there are 500 things, [graphical programming] is completely unusable. You zoom in and zoom out and you lose all context. I think it's just smokin' dope."