Setting up First Networks need help with hardware

[luxor3484]

Hi guys I am setting up my first server And need your advice regarding configuration.

What I'm trying to accomplish with the server
Create a domain with 20 client Pcs most running windows 7 pro and a few on Vista
File sharing With different levels of permissions for clients
Deploying software such as virus protection and employee monitoring
Remote access for clients to work from home if needed


Questions.
What type of raid config do I need ?
What type of partition do I need ?
What version of server do i need ?
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Below is the server I am thinking of buying. It's $2399 with free upgrade to 16gb of ram.

Dell Poweredge T320 Xeon E5-2420 6C 2TB 8GB WINDOWS SERVER 2012 STANDARD T310 ★★
Warranty 3 Year Dell Basic Hardware Warranty Repair: 5x10 HW-Only, 5x10 NBD Onsite
Condition Brand New
Chassis & Front Display Poweredge T320 Chassis with up to 4 x 3.5" Cabled Hard Drives & LED Diagnostics
Operating System Windows Server 2012 Standard 64-bit (RAID 10 setup or your preferred RAID configuration at checkout) - OS license included
Processor
Intel Xeon E5-2420, 1.9GHz Six Core (15M Cache, Turbo Boost up to 2.4GHz)
Hyperthreading w/ 6 Physical Cores & 12 Threads
Memory 8GB Memory (4x2GB), 1333MHz ECC RAM (Upgraded)
Hard Drives (Multi-Select) 2TB = 4 x 500GB 7.2K RPM 3.5" Cabled Hard Drive (Upgraded)
Hard Drive Configuration RAID 0, 1, 5, 10
RAID Controller Onboard PERC S110 RAID Controller (Supports RAID 0, 1, 5, 10 for SATA Drives)
Optical Drive 16x DVD-ROM
Network Adapter On-Board Dual Gigabit Network Adapter
Power Supply Single Cabled Power Supply, (350W) 80+ Silver
Video Card Integrated Matrox G200 w/ 16MB Memory
Remote Management N/A
Embedded Management Baseboard Management Controller
System Documentation Electronic System Doc, OpenManage DVD Kit

I/O Slots, Ports, Dimensions, & Weight
Intel C600 Chipset
(8) USB 2.0 compliant ports (2 Front, 6 Back)
15 pin VGA Connection
Dual Gigabit Ethernet NIC
One x16 slot with x16 bandwidth, 3.0, full-length, full-height
One x8 slot with x4 bandwidth, 3.0, half-length, full-height
One x8 slot with x4 bandwidth, 2.0, half-length, full-height
One x8 slot with x4 bandwidth, 3.0, full-length, full-height
One x8 slot with x1 bandwidth, 2.0, full-length, full-height
Maximum RAM Capacity: 192GB (6 DIMMs)
17.3" H x 8.58" W x 22" D (inches)
Shipping Weight: 50~65 LBs
Compatible & Certified OS
Microsoft Windows Server® 2012
Microsoft Windows Server 2012 Essentials
Microsoft Windows Server 2008 R2 SP1, x64 (includes Hyper-V® v2)
Microsoft Windows® Small Business Server 2011
Novell® SUSE® Linux Enterprise Server
Red Hat® Enterprise Linux®
Optional embedded hypervisors:
Citrix® XenServer®
VMware vSphere including ESX™ and ESXi
Red Hat Enterprise Virtualization®
UPGRADES AVAILABLE
OPTICAL DRIVE
$40 - DVD-RW Burner
MEMORY
$399 - 32GB (4x8GB) ECC RDIMM RAM
OPERATING SYSTEM
$99 - Operating System Installation & RAID Setup (You can specify any RAID 0,1,5,10 and size of the partitions that you want)

 

[s-h-a-w-n]

RAID considering you have 3 x 1TB drives:
RAID0: 3TB of storage at 3x speed, but very likely to loose data
RAID1: 1TB of storage at 1x speed, but 3 copies of your data, not likely to lose data
RAID5: 2TB of storage, speed is higher and the equivalent of one drive is dedicated to redundancy, good speed and data protection.
Combos are possible

Windows Server 2012 Essential is supporting up to 25 users, the Standard edition is not limited but is more expensive.
Thera are Linux server editions that can do this for a lower price but its more complicated.