Thank you so much for detailed answer. Couple more questions:

1. How much hardware resources should I apply to each instance. Per your advice I will be installing two VM's: dev VM and media VM. Should I go 50/50 of available resources? Or leave some for physical/host 30/30/40?

2. I have a spare 500GB SATA drive. Can I use it as a stand alone drive for backing up system files? or that's not a good idea?

1. The host, because you won't be (can't, per licensing restrictions) doing anything in the host that requires many resources (no file server, no IIS, no AD .... just Hyper-V), can be configured with the minimum required/recommended.  As far as the remaining ... it depends.  It depends on the usage and activity of the machine.  You CAN adjust this later (number of processing cores and memory) as a setting in the virtual machine, so you don't need to figure it out right now - you can simply adjust it as needed.  If you have 8 cores and 16GB available, I would assign 4GB and 2 cores to each virtual machine, then increase as needed.  Adding storage isn't as easy, but consider what you are going to run on each RAID array.  It might be tempting to through your host OS on the 146GB/15K drives, then configure your VHD's on the RAID 10 (or 5).  However, you will be putting your fastest storage under the host OS that will not be doing much of anything, while the VM's on the VHD's on the RAID 10 (7.2K RPM SATA) are doing all the real work.  You could, of course, create a VHD on the RAID 1 for faster storage, but you will be limited on size if it also has the 60-100GB OS partition.  My first impression would be to install the OS to the RAID 10, configure the VHD for the dev VM on the 146GB/15K RAID 1, then the CCTV stuff on the RAID 10 ... BUT it depends on too many things for that to be a recommendation, like where you need the speed the most. 

2. Yes, you can.  The PERC does NOT support non-RAID, so you can't "just use" it ... you need to create a single-disk RAID 0 with it - it will then be available as a new "disk" in Disk Management.

I will take this opportunity to strongly recommend AGAINST using cheap/desktop/consumer SATA drives.  They are unsuitable for use on enterprise RAID controllers, like the PERC.  You will likely have no end of issues with them.

All makes sense, I will give another thought to my drive setup. What about consumer drives designated for NAS, f.e. WD Red and Black series? I have two SAS 500GB 7.2k at home but was thinking about replacing them with WD Black series.

"What about consumer drives designated for NAS, f.e. WD Red and Black series?"

I wouldn't.  Take a look at the RE4's (RE = RAID Edition) ... WD has tested/validated them for the PERC.  WD has validated the Reds only for use in NAS devices (not enterprise RAID/storage systems), and WD discourages the use of Blacks in [enterprise] RAID.

"I have two SAS 500GB 7.2k"

500GB is more likely a SATA drive.

It's up to you.  If you have issues, there won't be much anyone can do to help you, and you can probably safely assume that any storage-related issues are because of the drives.  Just make sure that all your firmware (system and drives) is up to date so everything is operating the best it knows how, and be religious (Mormon style, not catholic style) with your backups.  You said 2x500GB in RAID 1 is "not enough" ... are you planning to put them in a RAID 0?  If so, then double your backup efforts/frequency.

The drive you mentioned (MM0500FBFVQ) is a "near-line" SAS drive ... not much better than a SATA drive with a SAS interface.  It would be cheaper to do SATA without sacrificing much performance/reliability (comparing with enterprise, not consumer, SATA).  Food for thought:

500GB Black SATA (7200RPM) - $70:
http://www.newegg.com/Product/Product.aspx?Item=N82E16822236345

500GB RE4 SATA (7200RPM) - $87:
http://www.newegg.com/Product/Product.aspx?Item=9SIA24G1740181

1TB RE4 SATA (7200RPM) - $125:
http://www.newegg.com/Product/Product.aspx?Item=9SIA24G15S7205

In comparison, here is a 500GB Near-Line SAS (7200RPM) drive - $170:
http://www.yobitech.com/ProductDetails.asp?ProductCode=T349H&click=1098

If you wanted to get serious about performance, without going the SSD route , this is what you would be looking for:

600GB (15000RPM) - $275:
http://www.serverhdd.com/hard-drive/sas/sas-6gbits/600gb-15000rpm/t335r

To me, going with an RE4 is a no-brainer ... $17 extra for a drive that WD says will work on your controller, vs. saving $17 on a drive that WD recommends you NOT use on your controller.

BTW Thank you very much for help.

I dbl checked those drives - MM0500FBFVQ, so they are SAS. 500GB in RAID1 is not enough and the SAS prices are quite high for my home use.

So the problem I'm having is either getting new consumer SATA drives or used SAS drives of ebay. I'm leaning towards new vs used.