Custom-built Server

Hi,

I'm building a Server for a small business (up to ~5 Workstations... not much growth after that - it's a tattoo shop)... and was wondering if you guys could give me feedback on this build. I've made some minor mistakes before building Small-business Servers... And this time I'm looking for a 'no-mistake' build, if you will...

http://www.newegg.ca/Product/Product.aspx?Item=N82E1681...
- Antec Sonata III 500 Mid Tower + Antec (Earth Watts) 500W Power Supply: $140

http://www.newegg.ca/Product/Product.aspx?Item=N82E1683...
- Microsoft Windows Server Standard 2008 R2 64 bit: $730

http://www.newegg.ca/Product/Product.aspx?Item=N82E1682...
- ASUS Black 24X DVDRW: $18

http://www.newegg.ca/Product/Product.aspx?Item=N82E1682...
- 3 x Western Digital RE4 WD5003ABYX 500GB: $255 ($85 each) -> 1 for the OS + 2 for a RAID 1 Mirror

http://www.newegg.ca/Product/Product.aspx?Item=N82E1681...
- ASUS Z8NA-D6C Dual LGA 1366 Intel 5500: $280

http://www.newegg.ca/Product/Product.aspx?Item=N82E1681...
- Intel Xeon E5506 Nehalem-EP 2.13GHz: $239

http://www.newegg.ca/Product/Product.aspx?Item=N82E1682...
- Kingston ValueRAM 6GB (3x2GB) ECC Unbuffered DDR3 1333 Server Memory: $78


Total comes to $1740. (For comparison sake... I built the exact same configuration on Dell's site... and it came to ~$3200)