This is a list of the things I use literally every single day, and that I would be lost without. Like a blacksmith has hammers, I've got these things. A lot of them are free, and some of them are not. In total, this represents less than $200 of software.
For significantly improving your quality of life, that's a completely acceptable cost to me, especially because I make my living with this stuff.
I'll do an Android version of this list at some point. It'll be similar tools, albeit without the code editors.
##Webstorm Webstorm has solidified it's place in my permanent setup when I saw this video by John Lindquist. It shows what you can do when you combine live editing in the browser, insane refactoring tools and a far more powerful platform (with real autocomplete) than SublimeText.
In my mind there's nothing that does as much as Webstorm, as well as Webstorm does it. Nothing holds a candle to it. Yes it takes a while to start, excellence takes time. Extremely worth checking out.
##Alfred my alfred theme
Though it's not directly related to dev (until you add this), it's a killer way to get a ton of stuff done extremely quickly. You can grab stock prices, check the weather, quickly search for gifs, use it as a quick calculator, the list goes on and on.
There's a huge list of things you can add to Alfred, that's a never ending, constantly evolving list.
##Dev Doctor Works directly with Alfred to get you documentation as soon as you can type it. Totally worth the few second install and the price.
~$0 Dev Doctor
Moves windows around, it's free, it's simple, never had a problem with it. It gets installed immediately with any new OS X install. Lots of key commands.
Not that I like testing for cross-browser issues, it does help to have a couple more OSs on your machine to try stuff out in. Microsoft has helpfully posted a bunch of images of Windows for free just for testing. When you pair VirtualBox with the unbelievably good Vagrant and as many distros of Linux as you could ever possibly need, it's a killer combo that you can test anything in. Can't beat free.
When you have to use the command line, and there should be a package manager that installs/uninstalls stuff. Do you really want to install Git, Node, FFMPEG or anything else manually like some sort of rube? Well worth your time installing Homebrew.
ruby -e "$(curl -fsSL https://raw.github.com/Homebrew/homebrew/go/install)"
Then installing ffmpeg goes like this:
brew install ffmpeg
If you're a human, you have some things that you need to do. They probably belong in some sort of list (outside of your bug tracker). Put those things here. Also, plays nice with Alfred.
Compass has taken the annoyance of writing regular CSS and made it actually enjoyable. There's a ton of things inside that that make it well worth the relatively gentle learning curve and once you've got a solid way to do live-updating, there's no lag in between what you're developing and what you're seeing in the browser. Also worth looking at is Bourbon, a really great mixin library for Sass. I've also used LESS, I definitely like Sass a lot more.
Not worth writing vanilla css anymore.
You like to keep track of events and things so you don't forget them right? Google Calendar is about as rock solid as I've ever used or found. Not a lot of alternatives out there
~$0 Google Calendar
To get things into your calendar (and Google Calendar) in a sane way, Fantastical's got the strongest natural language processing I've used. It works very reliably to process text into an actual task with a date in a thing with a place attached to it.
##1Password You should not keep all the passwords to your things in your head. They get lost in there. 1Password handles them all well and in a way that you don't need to remember all of them. Integrates nicely with Alfred, works on Android, OS X, iOS, Windows and works very well.
~$50 (OS X) 1Password
##f.lux If you do work on a computer, sometimes at night, you owe it to your retinas to treat them kindly. F.lux will locate your computer and change the color temperature to pull most of the blue out of the screen when it's dark outside. The effect of this is two-fold. You are no longer looking into the color equivalent of the sun, and suddenly your eyes don't feel like they've been in an uncomfortable scene from Clockwork Orange. You'll mostly just notice your computer doesn't hurt your eyes anymore.
##Dropbox You have files in one place. You want files in another place. Dropbox moves them around for you.j
##Arq For irreplaceable things that live on your computer, a backup hard drive is not enough. Arq iteratively backs up to Amazon's infrastructure in the background. It works very well, and if your home is overrun by weasels, you have backups of your important things.
##DaisyDisk When you run out of space in a folder or disk, you generally want to know what is going on in there. DaisyDisk will show you what you're spending your disk space on visually, and clear some of that garbage out. Great stuff.