When I develop, I have Notepad++ (generally two to five sessions and 10-30 files each open) depending on whether it's framework or modules on the roll. When it's templates, it's Photoshop, and when it's Flash time, it's Flash obviously. When phase beta is done and dusted, I have FF, IE, Chrome, Opera, Safari on for obvious reasons, and depending on how the stars are aligned, IE7 on for a bit more or not. When it's time to do on-site tests, it's Filezilla + cPanel (or whatever the panel there be) see more + phpMyAdmin. I do heavy multitasking most of the time, so the toolset configuration changes as needed to help keep the focus in place, and I have my own little tools for most general stuff I need to automate and crunch out of the way.