I've been building websites for a while now, I'm by no means a seasoned web developer but I think my current stack is a fairly effective setup. Here is some details about the setup.
I've been using OSX for development for a while now. While I'm still a bit of a Ubuntu fan at heart, I don't like running Photoshop under WINE so OSX tends to be my preferred OS.
Right now I have a late 2011 13" MacBook Pro, it's not great for gaming, but it can survive a 6 hour coding session on a single charge.
Since learning how to SSH into my VPS, I've become really fond of using terminal for as much as possible. It's really helpful that Linux and OSX are from the POSIX family.
Homebrew / Homebrew Cask
I have a small SSD (120GB). Out of habit I like to reinstall my OS every 6 months or so to clear out my unused applications and files. I find Homebrew and Homebrew Cask are really handy for reinstalling my favourite applications quickly.
Sublime Text 2
I used to use Coda for developing, but I found the FTP features extra bloat which I never used. I love that I can configure sublime for my needs.
I used to use XAMP / MAMP and then OSX's built in Apache server, however I found it a pain to keep the configurations consistent between machines and similar to my server. I started using Vagrant a few months ago for my PHP projects and I've not looked back.
I provision my Vagrant VM's with Puppet. I've been meaning to look into Ansible, but for now Puppet suits my needs.
Keeping CSS organised can be a big task. I started using SCSS over LESS a few months ago and really liked it, plus I can configure my server to compile the SCSS using a post-receive hook.
Staging / Live Server
Nginx (with mod_pagespeed)
I used to use Apache and I'm fairly confident with it. However, about 2 years ago I decided I should branch out and explore lighthttp and Nginx, mostly just to see what all the fuss was about. It took me a little while to start understanding what was going on, but once it started to click I thought it was something I should stick with.
The mod_pagespeed module is made by Google and looks through the HTML, CSS, JS and images making a best judgement as to if the file needs minification, concatenation or optimisation. It allows me to focus on writing maintainable code while providing the end user with the pretty quick experience.
My server is small & mostly just for me, Varnish Cache helps handle any spikes in traffic and keeps webpage load times down.
MySQL is fine, but I would rather put my eggs in a more open source basket. I found moving to MariaDB easy as it's merely a matter of uninstalling MySQL and installing MariaDB.
I use Git for version control and deployment. I've been meaning to learn Capistrano, but as I've really only deployed to a single server it's still on my todo.