NOTE: I created a new high-contrast fork of this style for personal use. If people like it then I'll support it officially and actively develop it:
4chan Dark Candy

I heartily recommend Zixaphir's slide-on side reply box in addition to this style: 4chan Slideout, Floating Postbox

v. 3 "The Zixaphir Update"

-- many changes as described here: http://forum.userstyles.org/discussion/25208/some-more-fixes
-- Post form improved
-- Super pretty captcha buttons
-- Pretty checkboxes
-- Mad respec to my boy

v 3.1

-- Calmed down the contrast around the post boxes
-- Added support for /b/ackwash tooltips

v 3.2

-- Corrected erroneous use on pages other than 4chan
-- Formatted CSS correctly