The folks at Bleeding Snort released an updated list of known malware-related domains yesterday, up to 9,400 entries now!  For those of you employing DNS black holes, proxy-based filtering, or doing other general research of malware based on domains, you should check out this exhaustive (and exhausting!) new list.  I frequently rely on this list to match against when doing research of spyware and related nasties.  Kudos to the Bleeding Snort guys for their hard work.