You should probably start with China and Turkey then
The subject of limiting by geography is actually fairly old and well discussed. There are a couple of bugtraq threads on the subject. On the balance of things however Russia and ex-CIS is probably not the worst offender.
If you want to depeer by country you should probably start with Turkey (email spam), China (relentless brute-force cracking of ssh, pop, imap and other password based services), etc. The sole reason C&Cs are not in China for example is the great firewall of China. With the chinese attitude to security and AUPs (and law and order in general) we are lucky that incoming connections into China are subject to "government inspection". If they were not...