Pat,
It looks excellent to me. Basically the ideal correlation is as close to 0 as possible, and most cells in the matrix are around 0.2 which is very, very good (uncorrelated). There are a few rows in the .5 - .6 range, but it is hard not to have a few like that with 7 systems.
1.0 means perfectly correlated and -1.0 means perfectly inversely correlated, both are bad for different reasons; if the system is close to 1.0 with another system it is multiplying risk/leverage to some degree with no diversification benefit, and if it is close to -1.0 then it is canceling out the trades of another system too much.
But in this data everything looks great. Nice work.
-Taric
edit: If you want to rank the systems (just based on how uncorrelated they are), maybe a simple way is for each row just take the average absolute value. The lower # the better. This doesn't include returns however so this alone doesn't tell you which systems are better/worse, but does give you a good idea of how well each system is behaving as a "team player" in your portfolio so to speak.