I've been using Microsoft Visual Studio 2003 at work for development work, and it has mainly been very good. I discovered today that it's find and replace function includes support for Regular Expressions. "Awesome", I thought — and anyone who knows about Regular Expression (reg exps for short) will know why. Regular expressions are essentially a very powerful syntax — almost a language really — for doing pattern matching and replacing. The task I needed to do today was remove all whitespace (spaces and tabs) from the beginning of every line in a text file, but nowhere else. A regular expression search and replace makes this trivially easy — just s/^\s*//g as a Perl command, for instance.
OK, rant over.