w3school.com: HTML, CSS and other web things.
Dither Me This: Dithering website.
Retro Image Tool: Another dither tool. Has some presets for retro stuff.
Playscii: A neat programm to make ASCII art in.
int10h.org: Has a lot of oldschool PC fonts. Badger's 8x14 IBM-EGA font comes from here.
nindestruct.com: best archive for NIN fans. I also got LITS font from here, but it's not used due to error inside the font.