Garr Reynolds is discussing about criterias of good or bad logos based on this years fifa world-cup logo in his blog.
According to Paul Rand (1914-1996), the effectiveness of a logo depends on several elements including;
• Distinctiveness
• Visibility
• Usability
• Memorability
• Universality
• Durability
• Timelessness
Read his article and proof logos you see on this seven criterias 
In my opinion there are several very bad logos out there but I am pretty satisfied with the “red cross” for example.
