Jesse James Garrett, experience designer. I co-founded the first user experience consultancy, Adaptive Path, and now serve as its Chief Creative Officer. I also wrote one of the first books on UX, "The Elements of User Experience", a little over a decade ago. So I've been at this a while.
I was a Mac guy back in the bad old days when it wasn't cool. Still am. I switched from desktops to laptops around '99 and have had a succession of PowerBooks and MacBooks since. I've never gotten the hang of using an external display, though. I prefer a mouse for precision work – I have a nice symmetrical Kensington wireless -- but most of the time the trackpad suits me just fine.
OmniGraffle is still my go-to for diagramming and wireframing. I know a lot of people who work in Illustrator, but I find OmniGraffle just naturally better suited to the work I do. Keynote for presentations – and sometimes prototypes! You can create a pretty high-fidelity mockup of an interactive screen experience with Keynote's drawing and animation tools. Photoshop for image editing, which frankly I don't do all that often. Text composition in TextWrangler. Avoid Word at all costs. Spreadsheets in Excel, however.
All of that said, for the core experience design work, digital tools only come into play at the very end of the process. I spend far more time at a whiteboard or scribbling on sticky notes when I'm designing something.
A 15-inch MacBook Air with retina display, >1 TB SSD, and a high-end GPU (for games). Yes, I know this product doesn't exist. You did say "dream"!
As an experience designer, I'm fortunate in that pretty much anything can serve as inspiration. The more you do this work, the more you inevitably view the world in terms of systems and the people interacting with them. I love being able to experiment with translating patterns across domains: taking a physical interaction and making it digital, or vice versa.