"How do I install drivers while the install media is in?"
There is no "F6" like with older OS's. When you get to the screen that says it cannot find any hard disks, click the Load Drivers link, then browse to the drivers on USB, floppy, or DVD (it is safe at this point to swap the installation DVD to load the driver).
"Raid is already configured so that isn't an issue."
If it came "configured", I would redo it. Like formatting before installing an OS, it makes sure you are starting with a stable foundation.
"System Management - Not really seeing what you mean here."
Systems Management (called OMSA - OpenManage Server Administrator) is the software that should be installed on every production server and is used to manage and monitor the system - fans, temps, voltages, system logs, errors, monitor disk and array health, changing RAID levels/expanding RAID arrays/replacing faulty disks on the fly, and even changing BIOS settings from within the OS, among other things.
I only pointed out the shortcomings of the 2850 as a "desktop" because many people plan to use it as a regular PC and are later disappointed with the things it can't do.
So, what exactly are you going to do with it? Is it cost that is driving the use of a client OS? Uncomfortable with using Server OS? Many people run client OS's on servers and are fine ... just curious as to the reasoning. BTW, you can install a feature called Desktop Experience that converts the basic UI to a Windows 7 UI for a more familiar feeling.