Some people like the online service from Crashplan.
Hard drives are hit 'n miss but in my experience, WD Red are garbage. The RE4 are better but overpriced. Seagate has been crap for a while. Samsung was decent for a while.... I've had best luck with Hitachi and Toshiba.
You don't want RAID. When RAID arrays go up in smoke and you don't have a backup it's a lot more expensive for data recovery services. Go with large single disks. Be wise and perform regular backups no matter which you choose.