This was the title of one of my KinkForAll presentations. I taped it, and may put it up shortly.
I do have some extra information, and some errata.
A question was asked about how long Hepatitis lives on surfaces. From
a few different sources, it seems as up to 4 days. One study (animal testing) found
that dried samples were still infectious at 16 hours, and possibly up
to 4 days, but not longer than that.
I have a few sources about infection rates of different STIs, and I will
get them into a blog post soon 
I do want to correct a statistic. According to am HIV per act risk paper, the per act risk of HIV
transmission by an anally receptive partner with an HIV infected Top
is five in 1000, not 1 in 1000. I apologize. In any case, the article is a fascinating (at least to me, being a statistics geek) study in how to quantify risk acts, and our choices of partners and activities.