I am designing my first Wordpress theme and I was wondering about how readable gray text on white background is. At the moment I'm using #555 text on #fff background. The only clear suggestions I've found were on w3.org site (the WCAG 2.0 guidelines). They state the following:

Contrast (Minimum): The visual presentation of text and images of text has a contrast ratio of at least 4.5:1
and
Contrast (Enhanced): The visual presentation of text and images of text has a contrast ratio of at least 7:1
#555 on #fff apparently is 7.5:1, which is even over the guidelines. I'm wondering what the experts think about this though, since I notice most websites are using #000 to #333.

The thing is, I find #000 on #fff rather harsh on the eyes (might have something to do with my outdated, 6 year old LCD monitor) and the gray text looks much better to me, but perhaps it's not as readable when we're talking about longer articles.

What is the "brightest" text color you would choose for an #fff background? Do you think #555 text is too much?