|Click to embiggen.|
First of all, there is a lot of destruction in null sec / wormhole space. Eyeballing it, I'd say close to half of all destruction is in the red spectrum, with the rest divided up between low sec and high sec in a 2:1 ratio (i.e. low sec has twice as much destruction as high sec).
Next, there are 7930 systems in EVE broken down into these distinctions (stolen from this thread here so yell at me if they are wrong):
High sec: 1090
Low sec: 817
Null Sec: 3524 (of which 230 are not connected, i.e. Jove Space)
Translated into percentages and combining null sec and w-space since they are the same colour on the chart, we get high sec as 13.7% of space, low sec 10.3%, and null sec/w-space as 76.0% of space.
Thirdly, if you took out the top 6 systems from high sec with the most destruction, the amount of space left over for high sec destruction drops significantly.
In other words, low sec sees more destruction per system spread pretty evenly than any other part of EVE in 2013. If you are looking for consistent PvP action, low sec is the place to be.
Now, about the grey coloured circles, they are low sec systems I recognized as part of the Gallente-Caldari faction warzone and we visited most of them on our roam last Friday night and they are frequent destinations for our fleets. If I coloured in the Minmatar-Amarr warzone systems, most of the other large low sec destruction circles would be grey as well.
In other words, Faction Warfare: its where consistent and destructive PvP is at.