My company is currently looking at bringing "in house" our corporate e-mail services. We have outgrown the ability to have some manage the service for us. We are presently looking at Windows 2003 Exchange server for our needs. With 500 e-mail accounts, and growing, what are your opinions of the product? Any recommendations for hardware? We are historically an IBM shop so I was thinking about something like a x346 server with SCSI and set up in a RAID 10? How is the software for SPAM filtering? Any recommendations for Anti-virus intergration? Finally, how does the licensing work? Do you have to purchase a seperate license for an OS to run it on or does it include the license? Standard or Enterprise edition? Any advice would help.