Your ssd is large enough for window and program installation. So go for the os and program in ssd and storage in hdd strategy. RAID setup? what other disk do you have? RAID ssd with hdd is a thing to do if you want to totally waste your money.
Intel SRT has a maximum cache size of 64GB, so if you think you could make due with 64GB for your OS partition, you can have the best of both worlds. Just partition your SSD into two parts and use one for your OS and the other as your SRT cache. Voila, fast read/write for your OS partition and fast read times for your other apps and games.