Suggestion for Networking Architecture

[smallbusiness]

I was looking for a place to post this and landed here. I'm a small business owner (~25 people) and have a Windows Server 2003 based network. Its old and in need of a complete overhaul (software and hardware). I'm looking for suggestions on a complete network rebuild. I have a brand new Watchguard firewall and a T1 connection to the world. About 1/2 of our employees are Road Warriors so remote access to network resources is a must. I'm pretty versed in the IT arena but would like some suggestions. As a small business cost is always a consideration but I'm willing to spend $'s to stay on top of technology. Here are some basic requirements (in no specific order):

1. Email services (shared calendars, etc.)
2. File Storage Services (We need about 1TB of network active storage. We have about 4 TB of archive storage.
3. VPN access to network resources
4. Multi-level user security access
5. Printing, scanning (we have a Xerox network scanner), IM services, FTP.

I would like to keep things relatively simple for setup and management but also want flexibility. I don't know if I should just scrap Windows Server and use a Linux Server with SMB resources? Should I use ESXi and run all virtual servers?

I'm looking for some good constructive suggestions!

[Zachary]

If you havent backup the system state then you cannot get to rebuild your domain, so you need to have two domain controlers, DNS servers, and backup system states. Then you can install a second DC on the network for the existing domain, move the roles to the new server, create a new user in AD on the old server, take old server offline and make sure the users can still login to the domain user the new server.