Locut0s
Lifer
I don't. Since most sites are designed for 4/3 displays they look much better when the window takes up about 1/2-1/3 of the screen on a wide screen. I've seen some people use the whole screen though and I just find this hard to stand on most sites. Here is a pic of how I usually have my browser window sized:
Web browser / Desktop
Web browser / Desktop