I have used many tools over the years, but on a daily basis, these are my go-to’s, listed here generally in order of use.
I use sticky notes to quickly generate ideas for content or widgets. They are especially useful if I am working with a group and want to gather feedback from everyone present – each person writes or draws. I use different colors to represent different types of content or ideas. I use Sharpies because they are thick and more conducive to quickly sketching/thinking.
I use large post-it paper (18×24) to stick to the wall and capture notes and stickies. I often don’t have the luxury of dedicated wall space so this allows me to take the results of a working session with me.
I’ve been using Axure for about 8 years and use it almost every day in my work. It’s an incredibly versatile wireframing tool. I might die without it.
usertesting.com is great for testing basic interactions where you don’t need a very targeted user group with knowledge of your domain. It’s unmoderated so you don’t have the opportunity to ask probing questions and have a dialog with the participant, so you’ll need to anticipate issues and include follow up questions in writing.
I use Adobe Illustrator for visual design comps when Axure doesn’t fit the bill.
I use Adobe Photoshop for creating final images for production. I do not do layout in Photoshop – it is not an ideal tool for quickly generating ideas.