I’ve moved on from using MAMP for a development environment to using Vagrant and in particular the Varying Vagrant Vagrants box, which is very popular and highly recommended for WordPress development.
I use the Mac app Vagrant Manager, which gives me a nice UI to control my Vagrant boxes.
Then I use Variable VVV by Brad Parbs, which helps enormously with site provisioning, and means I can setup a fresh WordPress install in a matter of moments.
I also use VVV-dashboard by Leo Gopal, which provides a nice dashboard to access all my dev sites and other tools on the Vagrant box.
I used to use Codekit quite heavily and I am still a fan, but I now tend to use Gulp for all asset compilation.
Underscores is a great WordPress starter theme and highly recommended, and was the basis for my own starter theme, lh, which I now use for all custom themes as it features my Gulp configuration and many of the best practices I’ve learnt so far as a front-end developer.