Who are you, and what do you do?
What hardware do you use?
My main machine is a 13" unibody Macbook. I upgraded the internal disk to a Corsair P256 SSD about a year ago, and I'll never go back to spinning-metal disks. That one upgrade was like buying a whole new computer. I compensate for the slightly smaller disk size by carrying a portable 500Gb Seagate FreeAgent USB disk in my bag for large media.
At the office and at my desk at home I plug into a dock from Henge Docks with a 27" Cinema Display. I've never been able to get my head around the two screens of an open laptop and a big monitor; I prefer one large screen.
I find it very hard to work without music and I always have an eye out for the latest portable hifi in the price/performance sweetspot. The home dock has a pair of Bowers & Wilkins MM-1 speakers and I have a pair of Audio Technica ATH-M50 for the office, both of which sound wonderful and fit neatly into a suitcase for travel too.
Away from home, I regularly carry a 3G iPad, a Mifi and a Canon 5D Mark II camera. For short trips when I'm not coding or speaking at a conference, I leave the laptop behind and go iPad-only. I have a couple of microsims with data plans for different countries which I swap over when I get on a plane.
And what software?
For coding, I'm a traditionalist - I run everything in vim and Terminal (although these days I've gone a little soft and use MacVim.app). Currently I'm experimenting with using Vagrant to create VirtualBox Unix VMs for project work, to hide away all the little differences between the OS X Unix variant and the usual Linux server environments.
The only really big GUI apps I tend to use are for media - I love the power and workflow of Adobe Lightroom for photographs, Traktor and Ableton Live for tinkering with music, and Keynote for presentations. My favourite desktop twitter client is Yorufukurou, which I admire for its keyboard shortcuts and humility of UI. Chrome is my web browser.
As I travel a lot and have had laptops fail on me while on the road, I try to make everything as replaceable as possible. This means using web-based apps or cloud-backed frontend clients as much as possible: feeds via NetNewsWire with Google Reader backend, Notational Velocity with Simplenote sync, Omnifocus synced via MobileMe, Instapaper for reading. I use a dedicated mail server-provider (Tuffmail) for my email hosting because their spam filtering is fantastic, but also forward all non-spam from its inbox to GMail for mobile use. Code, both opensource and private projects, lives on github. I make regular automated backups, both to a Time Capsule (at home) and to rsync.net (from everywhere else). Important files that I want to share with the iPad are also in Dropbox.
What would be your dream setup?
I think pico-projectors are going to get really good soon - I've seen impressive demos from Microvision using an iPad as a source. And just like everyone else I'd love a more powerful Mac. However I'm hooked on portability and I'd use an 11" Macbook Air if I could suffer the performance drop. So I'd like the power of a Mac Pro in a 13" package, please.