Here's a list of the tools I'm using to build Curry Finder. I'm not claiming any of these to be the latest or greatest, but they're suiting me pretty well for now.
Xcode
Xcode 5.1 beta as I type. I'm building the app with storyboards - because every line of code I don't have to write is one I can't get wrong! And Curry Finder seems to be a good fit for storyboards.
MAMP
Mac / Apache / MYSQL / PHP - really simple solution for setting up local MYSQL and Apache servers. One click and they're up and running, delete a folder and it's gone.
Espresso
I originally got this as part of a MacHeist bundle, and hadn't really touched it, but it turns out it makes a pretty good PHP editor. It's got code auto complete and auto publishing, but I'd like it to include more complete syntax checking (php -l).
Evernote
I originally used this to gather my thoughts, but it's transformed into a semi-project-management tool. Using the "notebooks within notebooks" feature, I have a notebook for apps, and within that a notebook for each individual app. Each app then has notes per version (one for design, one for development, …), the development one containing to-dos for my feature "backlog", tech debt, bugs etc. It's a sweet little setup for a solo developer, and I can update it from any device I have to hand. If you have a pro account, then you can share notes for other (non-pro) Evernote users to update.
Bitbucket
Git repo by Atlasian. It's free - what else can I say? Oh, and it integrates seamlessly with…
Tower
Git client. I've been using Tower since it was released, although if I was picking one now I may have gone for another free Atlasian product, SourceTree. The apps are very similar in scope, although Tower has the better looking UI.
Acorn
Image editor. A polished, Mac native app, with the vast majority of Photoshop features I'll ever need, at the same price as 1 month of CC.
Charles
An HTTP proxy that easily allows you to monitor web traffic. Great for testing out those web service calls. You can see the request and response in various formats, blacklist urls, add breakpoints. Very useful.