Here's another screen shot, with magnification 300% so you can see the details of the font:

http://www.solipsys.co.uk/images/UnreadableLightGrey2.png

It's the weight of the font that's the problem.

I'd love to know what you're doing that causes this - in part it's problems like this that lead me not to use any significant styling at all on my site.

You have no contact details in your profile, otherwise I'd've emailed you.