Yet another type (3) of attack may be a miner creating and solving a large bock to cause relay nodes and some clients to crash.   Rumor is that the 1 MB limit was introduced to prevent hypothetical type (3) attacks, or some similar one.    But there was no such attack during the 20 months or so in 2009 and 2010 that bitcoin operated with a 32 MB block size limit; and it is not clear whether such a rogue miner could do much damage except to himself.