Migration

Recently I migrated from SBS 2000 to SBS 2003. My work is easiest now.
My company?s network was with Linux Firewall, and SBS 2000 server. Now we have a Linksys router with Firewall, and SBS 2003 server. Also we buy E-Trust antivirus solution for server and all the computers in our LAN. We configured ISA server on the server and firewall clients on workstations. Also we configured Active Directory with very strong security policies. That?s the most important things what we does. I?m wondering what your opinion about those is. ?? I?m waiting your comments.