Almost a year ago I switched to using Sublime Text and soon wondered how I ever lived without it. Sublime text is awesome, but there are many other works out on the net talking about how great it is, so I won't try to convince you. You can google why sublime text is awesome if you are curious though.
I was using Netbeans at the time and I went from primarily working on PHP applications to Rails. I didn't need an IDE like that anymore and was looking for a lightweight editor. I also was switching from development on Windows to OSX, I liked Notepadd++ but it wasn't available in my new environment. After brief encounters with Text Wrangler, Komodo Edit, and TextMate, I soon found Sublime Text and have been using it ever since.
From day one though, I always thought it was missing a feature. I had grown to love the way Netbeans displayed a color coded gutter for code modifications if you were using Mercurial. I tried to find something like that, I used the annotate feature of the git plugin but didn't like that the code lost it's syntax highlighting. So I finally decided to spend a weekend and build a plugin myself that did this.
I submitted it to sublime package manager and despite the fact that it initially didn't even work when installed via package manager (due to a directory name mismatch) it immediately started gaining a lot of traction.
It was talked about a lot on twitter, featured in Pycoder's Weekly, and on github it was the most starred python repo for the week when it was just a couple days old.
I was shocked. I mean I really only made this for myself, I had no idea everyone else would like it as much as I did. But they did, so suck it! just kidding. If you haven't checked it out yet its really cool. It shows you what lines were changed, added, and removed since your last commit:
In the screenshot above you can easily see at a glance that lines 10-13 (the new_method) were added. You can also see that lines 15 and 16 were modified and that one or more lines between 17 and 18 were removed (which would explain the indentation.) It also helps you spot debug statements you might easily overlook and accidentally commit (like line 23.) Sometimes I accidentally type into my text editor when I don't realize the window is selected, it makes that more easy to spot too. It really is quite useful.
You can install it via package manager by the name GitGutter. Check out the Read Me for more information.