Who are you, and what do you do?
My name is Gabe Newell. I'm the co-founder and president of Valve, a videogame developer.
What hardware do you use?
I have an overclocked quad-core Intel CPU, SLI NVIDIA graphics cards, an ancient Microsoft ergonomic keyboard I refuse to give up, and a Razer gaming mouse on a Valve mouse pad. My desk is an all aluminum Lian-Li, and I have a Panasonic 42" HD TV as my monitor. I have an over the air HD receiver, and use Snapstream's BeyondTV as a PVR.
And what software?
I've downgraded to Windows XP and Office 2003. I've tried Chrome, and gone back to Firefox. In addition to MS DevStudio, we use Perforce and IncrediBuild. For RSS, I use Bloglines.com. And we have a bunch of tools we have created ourselves.
What would be your dream setup?
The main thing is to have a process more than a single particular setup. I've tried all sorts of home-built systems, including water cooled, phase change, etc... The conclusion I've reached is that upgrading every 6 months is more important than trying to get the fastest possible system at one point of time. The time and energy I used to spend optimizing my hardware I now spend making sure it's easy to swap out my current machine for a new machine with the least downtime.