I am using now MT-Blacklist for deSPAMming of Comments
MT-Blacklist
looks very nice so far. The good thing about Movable Type is, that it has quite a bit of community development behind it. I am thinking of moving to WordPress because its all free and also supported by KungLog (now ecto), but the community involvement does not seem to be quite up there with MT. And I am of course too lazy/no time to get involved. :)