I too fall for the big monitor fallacy, I like running an external monitor at high rez. One screen with a web browser and the other with a split terminal vim split in 2-4 panes. But it's really just moat. I could do well with just one terminal and a little better short-term memory. If I work focused and take breaks, I can work with just one terminal window @ fullscreen, control-z for task management and a web browser to switch between.

Just look at zedshaw. He works with a couple of junk linux laptops and a white macbook, and gets the shit done. The hardware doesn't matter that much, especially if you're doing your work in the terminal most any computer is fast enough.

I suspect though, that when it comes to guitars he has a little more equipment jones.

I used to work on a white macbook 1:st gen for years, but I bought a new mbp 15" a couple of years ago so that I could run vmware and not have the machine melt every time there was flash on a webpage.

In short, equipment doesn't matter that much (unless you're running an IDE), it's more important to take breaks and stay focused.