This table contains data based on my own experience, so it can be wrong, it can be subjective etc.
TGPs marked with green "$$$"
used to send quality traffic to my galleries,
I got signups on regular basis from them.
The "Max Traffic" column contains data from 3rd-party counters like SexTracker,
it's the top value
for each TGP I seen since 2001; traffic in 2007 can differ essentially. For example, EasyPic.com
in 2007 has way less than 750k daily traffic. You can get an idea about traffic for each TGP from alexa.com traffic ranking graph - just point the mouse over corresponding "Max Traffic" cell.
Last column, "to 1 gallery" contains the best result for a single gallery listing from a TGP.
Again, it's my own experience only, and other gallery posters can have different results.