Here are a few of my favourite every-day dev tools that make life easier.
PHP Storm
This full IDE is my favourite development environment. Even if you don't use all the features for linking up GIT, compiling LESS and even tracing the execution from your browser, the basic tools of code hinting, class navigation and error highlighting speed up development time.
MAMP
This local Mysql, apache and PHP setup for Mac allows you to really quickly set up a full web server on your local machine. It allows you to work locally in exactly the same way you would on your remote server.
Sequel Pro
phpMyAdmin is a great web-based tool for managing databases, but if you need to transfer large amounts of data or perform complex, large queries then it can sometimes fall down. This is when a local mysql client like Sequal Pro comes in handy. It's small, free and easy to use.
Firebug
It's been around for a while and for many it's been replaced by Chrome's developer tools, but I still think it's the most powerful and reliable way to dig in to how a page has been rendered.
Macbook Pro
I've never been particularly an Apple fan-boy. I'll quite happily work on PC and Mac and I think they both have something to offer. But after buying my first Macbook I have to say it's definitely worth the money and I'd never go back. Not only is it a well built machine, but because the underlying OS is based on Linux, as a developer, it's much closer to working on a production web server.