1. A text editor that is powerful, stable, and basically good for programming. I rely on "vim" almost always, but Xcode is a nice fallback. 2. A powerful term

1. A text editor that is powerful, stable, and basically good for programming. I rely on "vim" almost always, but Xcode is a nice fallback. 2. A powerful terminal. On Linux, "aterm" is the best I have ever found. On Mac, I prefer MacTelnet but Apple's Terminal is pretty good. 3. A suite of infrastructure tools. I've been in the Unix universe for many years, so it's hard to imagine anything except the usual suspects: ls, find, grep, awk, xargs, etc. all joined through shells, Perl and Python. These are definitely "must have"; even if they don't qualify as a single app, they certainly qualify as a single entity I couldn't live without. (And having stumbled my way through Windows' inadequacies, I now know this painfully well.) 4. A web browser, and by extension, Google. I like OmniWeb the most, though I use Firefox at work. I've even been known to use Lynx, or the occasional automation through "wget". There is simply no faster way to get information anymore; I'm more likely to web search for tools than run "man" pages, even. 5. E-mail. I prefer a trivial "send" interface (I like basic command line "mail" sometimes, though "pine"/"alpine" are my favorite). I do use Thunderbird and Apple's Mail quite a bit. I am not a fan of overly complex tools, but the ability to tag and search/filter mail by tag is a really compelling Thunderbird feature.