The equipment is not so important. I have written some great applications hunched over my 9" eeepc. Generally, I use a 24" monitor and happy hacking keyboard, though; which definitely makes things easier. (It also makes it easier to get distracted by HN, though.)
I spent a while coding on a 15" Lenovo laptop and it works because the resolution is 1920 x 1200. I still like to use multiple monitors but it's not really necessary.
Worst coding environment was probably one of those CRT iMac's running OS 8.
