The main things I like in an IDE are discoverable functionality (e.g. in Visual Studio, variables that changed since the last breakpoint are red--I'm sure gdb h

The main things I like in an IDE are discoverable functionality (e.g. in Visual Studio, variables that changed since the last breakpoint are red--I'm sure gdb has acquired this ability since I first looked at it but it's questionable if I'd've ever gone looking for it on my own) and refactoring (e.g. changing the name/signature/return type of a method throughout your codebase). IDEs are typically big wins when you're writing in statically typed languages (especially ones without a REPL) and less so in dynamic ones - in Python I'd be perfectly happy in Notepad for at least 75% of my programming because I do so much exploratory programming in the REPL.