New 8 drive Nas

Hi I'm designing a new nas with 8 1TB drives and I have a $200 for a hardware raid card. I am stuck between Raid 50 and Raid 6 / Which raid card to go with. Any help would be appreciated. The motherboard I'm using is an Intel DP45SG   and I have two pci-e slots filled with dual gigabit adapters and one pci slot with a gpu (Total ethernet bandiwth of 5Gb's because of NIC teaming. I have both of the x16 slots open and I'm pretty sure they also can take an x8 or x4 raid cards. .Any help finding a raid card / configuration would be appreciated. 

For a raid card in that price range I think a Dell Perc H700 would be doable but I think you can only use drives that Dell specifies which is a limitation. with N-2 condition Raid 6 is for mission critical data where you want that little extra protection over Raid 5. Multiple terabytes can take a long time to rebuild. Raid 50 would have a higher performance but wouldn't be as safe as Raid 6 (from a probability standpoint). 

Are you having a lot of workstations/servers polling from this Nas? or do you need just raw throughput for a single user?