I tried using Mail and I found too many problems with it. The main one being the use of AppleDouble to encode attachments. Most of the time, my mail recipients receive two files and it creates a lot of confusion. Word and Excel files won't open, picture files will sometimes be corrupted, and some mail messages are never received. I have Office:X so I switched to Entourage and haven't had any problems whatsoever. Entourage is faster, more compatible with mail standards (ie. use of Uuencode), and there's no limit to what you can do with the filters and scheduling. The only downside is no support for AddressBook.