Colour Scheme Generator

[CptStern]

invaluable tool for matching/complimentary colours

http://www.wellstyled.com/tools/colorscheme2/index-en.html

it's mostly for web as only 256 colours are represented but it's a good guide nonetheless

 

[Raziaar]

Pretty cool.

I was using this one tool once that helps you determine how well colors pair together for contrast and stuff on websites.

And another for converting websites into certain color blindness types and using that to help as well for best usability by people with visual disabilities.

 

[CptStern]

ya this does all that

 

[Yorick]

I use Color Schemer Studio. I love it.

 

[Druckles]

Kuler has always worked for me.