I use the Dark Grey Digg theme, by josdigital [ Digg.com - Dark gray design ], which (to pour salt in the wound..) broke when Digg implemented the threaded comment "travesty".
All the comment headings were bright white, as were the reply-box padding - which when the rest of the site is grey, gets rather painful..

It was relatively simple to fix, only one div needed changed, and a few added.

Things fixed :
-Reply headers
-Reply boxes
- More comments links

Things still to sort :
- Buried comment header
- "View 123 replies to this comment" hover-colour
- "Add your Comment" heading background images (It uses rounded corner images)

Notes:
- This theme replaces the previous one, remove it before installing this one.
- The before/after previews make the background look noisy, which is just the GIF compression - it's solid grey..
- I've commented all my changes in the format /* [dbr|added]: description */ or /* [dbr|modified]: description */, should you want to fiddle with the colours et