You do not want to run RAID10 with a 80GB SSD, 2TB HDD, 2x 1TB HDDs. The result will be 160GB usable space with twice the sequential performance of the slowest HDD and random performance of the slowest HDD. Basically, you waste the performance of the SSD while wasting most of your HDD space.
RAID10 provides redundency or the ability to continue working in real-time in case of single (maybe two) disk failure. RAID is not a form of backup and does not protect from ID10T problems or kids. You are probably better off just backing up your media especially since HTPC usage pattern tends to be write-once data.
For your current setup, I would suggest running your OS and applications on the SSD while keeping your media/recording on the two 1TB HDDs. Then schedule periodic coping of your 2x1TB to 2TB.
I had hoped to avoid 2 or more drive letters; just seems inefficient to me. So if I use the 80G SSD for OS and apps could I setup the 2ea 1TB and 1ea 2TB as RAID5 or 6 and be happy?
My goal here is to set this machine up so I dont have any worrys/upgrades for at least a few years
Two 1TB and 2TB HDDs in RAID5 would yeild only 2TB usable.
Two 1TB and 2TB HDDs in RAID6 would yeild only 1TB usable. However, RAID6 requires 3rd party controller ($100+).
Both these options really waste the space of your 2TB HDD. The other option is a JBOD but you again would need a 3rd party controller. There might be software RAID options but I cannot recall of any free ones for Windows.