I started coding in the early '80s. All we had then were 80x24 tty's, dark background and a green or amber foreground. But ever since I got access to GUIs (first SUNs old sunview or suntools, or whatever it was called, later X Windows) in the late '80s, I've always used a black foreground and a light background. Something off-white. Currently I use 'wheat' as the background color - but that can vary depending on the monitor being used and the lighting conditions of the office.

As font, I always use a fixed font, typically the largest font that gives me 2 non-overlapping windows next to each other, and vertically I want to be able to have at least 2 24 line non-overlapping windows, with some room to spare. On the laptop I'm working off now, this means the font choosen is '6x13'.

This is in my .Xdefaults file, both on my laptop, my office workstation, and my box at home:

XTerm*font:                     6x13
XTerm*foreground:               black
XTerm*background:               wheat
XTerm*scrollBar:                true
XTerm*saveLines:                2500
Rxvt*scrollBar_right:           true

I never had a problem with it, not even in sessions lasting over 24 hours.