Need 2k3 Server Hardware and Specs Recommendations

Hello, I was wondering if any of you could recommend some Hardware Specs and/or prebuilt model #’s (ex. Dell, HP) for a new work server. It will be supporting 20 users, 26 PC’s, and 6 printers. I will be using the Windows Server 2K3 OS and it will be used in the following roles:

DNS Server
Primary Domain Controller (Active Directory)
Application Server (minimal)
File Server (currently converting all paper customer files to electronic)
WSUS Server
Printers will be networked through it

I would like to put the OS on a RAID 1 array, and Data/Files on a 500 Gb to 1 Tb RAID 5 or 10 (suggestions?) array. Also, I would suggestions on favorite backup software suites.