My development toolchain
The question comes up often enough on IRC that I thought I'd go ahead and share my development "toolchain" -- the tools I use to get work done day to day.
Where it begins...

My company provided Dell Latitude E6520. While it probably won't be playing Crysis anytime soon it's more than enough for the day to day coding and the backlit keyboard surprisingly comes in handy more often than you would think.
The operating system...

Ubuntu 11.04. I may be in the minority on this one but I actually like the changes brought in by the Natty Narwhal update. Where I used to use a launcher program to quickly find applications the Unity launcher now takes care of everything.
Coordinating...

Despite liking the Ubuntu 11.04 release I absolutely hate the default mail application, Evolution. To that end, I also hate the messaging application, Empathy. Here you have Opera which does triple duty: IM client, email and browser for testing. If you haven't tried it out, give it a shot.
Coding

I've got to give props to my buddy Joshua McNeese for recommending this one: PhpStorm. It strikes a good balance between the bloat found in most modern IDEs and the assistance it provides.
"But it costs money!" -- yes and no. JetBrains (the makers of PhpStorm) are kind enough to extend free licenses to individuals who have open source projects. I simply sent them an email with the address to one of my open source projects and was rewarded with a license.
Terminal

This one is easily one of my favorites. Tilda. It's a drop down terminal that hides when not in use. I can't tell you how many seconds this application has shaved off my workday. Need a terminal? Hit a hotkey, there you go. Want it to go away? Hit it again, gone. Always the first thing on any new laptop of mine.
Database management

I use SQLyog for working with my MySQL databases. I've liked the application so much that it's one of the few Windows applications I find myself installing Wine for on Ubuntu.
Repository management

While I'm usually dangerous competent enough to deal with my Git repositories in the terminal, sometimes it's nice to have a GUI to wade through commits and branches. Enter SmartGit. The application is free for personal use. It can optionally integrate with Github.
There you have it. All the (major) tools I use. Recommend something better? Use the same things? Let's hear it.