Will This Setup Work For Whs 2011

Newbie here and i'm building my first WHS 2011 and have the following for the build

- old Antec Case w/ 480watt PS
- MSI A55M-P33 FM1 AMD A55 (Hudson D2) Micro ATX AMD Motherboard
- AMD A4-3400 Llano 2.7GHz Socket FM1 Dual Core Desktop APU (CPU + GPU)
- 8GB (2x4GB) G.Skill Ares Series DDR3 1600 Desktop Memory
- QTY 4 - 2 TB Western Digital Red drives - Want to set this up in a RAID 5 configuration
- DVD +/- RW drive
- boot drive - still deciding if I should purchase one of the inexpensive SSD - budget < $80 OR use what I have extra at home (2) 80gb or (2) 400gb Seagate drives (they are a few years old, but not heavily used) They are currently holding data but I can dump everything to an external
- 1TB WD external drive and 500gb WD external drive - currently unused

Goal is to RAID 5 my WD red drives for a total of 6TB. Is this even possible with the motherboard I have? Would I have to buy a dedicated RAID card or is software RAID sufficient

What would you recommend for a boot drive? Use existing drives or purchase SSD. What size SSD as I know WHS 2011 can be installed on a ~ 60gb SSD

For PC client backups, should I save files under my RAID 5 setup or use one of my extra Seagate drives?

I believe the motherboard has 6 SATA ports

What can I use my external drives for or is it even needed?

I will mainly be using the RAID 5 drives for storing and sreaming movies, storing pictures and storing and streaming music
I also want to use this to record ip cameras in my house if this is possible - 2 cameras
I will probably want to backup 3 computers all running windows 7 and eventually 1 or 2 Macs

thanks for any input