Most datacenters will let you run mailing lists with no problems. The problems only come when you are reported for spam. If you go with a DC that does not care about spam chances are your servers are going to be on a lot of email blocklists already.
John W, CISSP, C|EH
MS Information Security and Assurance ITEagleEye.com - Server Administration and Security Yawig.com - Managed VPS and Dedicated Servers with VIP Service