Just be careful with that RAID controller. There is no backing plate, that model is designed to be mounted on the motherboard, you can pick up a blanking plate for around a tenner or make you own. Also there is no write back cache so write performance could be a limitation. Finally the cables are around 15 quid and make sure you get the correct one. There are 2 different a 1-4 fan out cables, one for the internal type connectors (which is what you need) and one for external connectors which is very similar but won't work.
Personally I am using this one, it has RAID 5 + write back cache with BBU.
Dell Perc 5/i SAS/Sata Server Raid Controller With 512mb RAM & Battery Module | eBay
Finally, not sure which NAS you are using but its going to have to be pretty quick, plus of course GB connection to a dedicated NIC on the server.
Personally I am using this one, it has RAID 5 + write back cache with BBU.
Dell Perc 5/i SAS/Sata Server Raid Controller With 512mb RAM & Battery Module | eBay
Finally, not sure which NAS you are using but its going to have to be pretty quick, plus of course GB connection to a dedicated NIC on the server.