Check what the host's policies are re: spam and 'adult' sites. I have heard, but not confirmed, that Dreamhost is 'adult friendly'
You don't want to be on a server that may be IP blocked because it hosts naughtiness, or because the host is lax about killing spammers or their hosted spammed web sites like enhancement, counterfeit, piracy, pharmaceutical or personal financial products.
You want a host that has a clear Acceptable Use policy, and a good reputation for rapidly and ruthlessly squashing spammers. You DON'T want a host that regularly appears on the email blacklists, relay blocklists or rfc-ignorant.