I also completely blocked the country of Germany. ha..
I am usinghttp://relays.visi.com <
I think it might have shutdown?
The only real problem I had was from Germany sending German links. Once I blocked Germany, Spam was down 99%.
That's the infamous Sober virus. I noticed that many viruses send the receivers IP address in the HELO command.
SMTP-Server = 188.8.131.52
Infected-Host = 184.108.40.206
Infected-Host sends HELO 220.127.116.11 which is definitely incorrect. I have successfully blocked lots of Spam by filtering out clients that send specific HELO names (my IP, my domain, localhost) and this does far less colleteral damage then just filtering a whole country.
P.S.: My MTA is qmail.