Gray on gray is awful. Does only one person like it? :-) Here's a fix for Firefox that doesn't need the overhead of Greasemonkey.
@-moz-document url-prefix(http://news.ycombinator.com/) {
td { color: #000000 !important; }
td.title a:visited { text-decoration: line-through !important; }
td.subtext { padding-bottom:2em !important; }
}