Video capture and editing on Solaris vs Debian vs Ubuntu

I am interested in doing some heavy video work. I have a ADVC 110 Video capture device, which I am using to capture VHS video tapes, which I will convert on the server to DVD format and burn to DVD's using DVD production software. I will also take the captured video file and split it up in parts and convert to other formats.
I will have a need to rip DVD video and encoding.

My question is for these tasks what setup do you suggest for the following.

The server that will be doing this work is:

HP Proliant DL-380 G4
Dual CPU's 3.20 ghz / 800 mhz / 1MB L2
5120 MB RAM
6 hard disks on HP Smart Array 6i controller (36.4 GB Ultra320 SCSI HD each)
RAID set to RAID 5 (5 discs) with one spare (6th disk)
USB, 2 Ethernet ports, 1 ILO port, 1 SCSI port

When it comes to the 6 disk raid I am setting up I was planning to use RAID-5 on 5 disks using the 6th disk as a spare. Do you think this will be to slow (due to the parity) since I will be doing so much video editing?
My other choice was RAID 1+0 (RAID 10). This would not allow me to have that extra spare. Which do you think would be best? I have at least 50 - 2 hour VHS tapes to capture and DVD's not included.

As far as the operating system I am still considering the one to use. I am concerned about security, so I am undecided as to how much proprietary software I will install on this machine. Flash etc, make me a little wary.

I have used Ubuntu on my laptop and have been very satisfied, especially with the community support. However I am looking to try something new and not sure what to expect as far as support and available software necessary to perform the above requirements (and others not mentioned).

I am deciding between Debian 6 (squeeze) and Solaris. I am probably going to install Debian on another laptop I have, and was thinking about Solaris for this server.

The video requirements are one of the major functions this server must perform, and I do not know to much about Solaris. What recommendations do you have concerning the video requirements, and how Solaris will work on this server hardware. Thank you.

Hey
Solaris would be good as a file server, but Ubuntu has a distro that is made for media editing. Maybe you should just use that. Whey fight if you don't need to.