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From the perspective of a non pro that is only doing my own site and non profit sites and club sites I use plain jane text editors. For straight HTML it is easy to load in a browser and refresh at will.
More often I'm working against the server so that things get parsed. Refresh and there I am. Since I'm remote to the server I connect with SSH and use console tools and mc to navigate, copy, delete, move, and edit files. Browser is ready to refresh. For heavy work I run everything over a VPN for security and speed.
Now if I was getting paid for work or had the money I'd pick up a PHP IDE and be even happier. ...
So I have a hacked up IDE of sorts. Several secure connections to the server, sftp connected, several browsers open, maybe a remote desktop to simulate being an anonymous internet user, graphics tools local, and several virtual screens to keep it all managable.