I use vi. Well, actually, I use vim, which is commonly installed as vi on Linux and BSD. I also (GNU) screen as a far more versatile way to have multiple code windows open than vim's buffers and windows, however I do sometimes utilise the latter.
> 1). What are your top five must-haves in an editor?
I don't know that I can come up with 5 "must-haves", but the biggest reason I use vi is because it doesn't fence you into a beginners mode. I guess the second thing is that I don't have to use the mouse, followed by multiple-file support. And for error-checking, I have to be able to goto a specific line by number.
> 2). Why is your editor of choice better than other editors?
Mostly because I know it! :-) Plus there is a tendancy for IDEs to heavily use the F-keys, the cursor cluster and key-combinations.
> 3). Why is your editor better than an IDE?
> 4). Can you estimate how much more productive you are with an editor versus an IDE?
I've yet to use an IDE that I can enter or edit code quite as fast as I can in vi. Especially coupled with screen.
> 5). Do you use plug-ins with your editor? If so, which ones and why?
Syntax highlighting is exremely useful. The biggest advantage is that it can tell you the names of built-in functions...