As far as drives go, you can go crazy with all the options there are today. I'm not sure exactly what you would want a RAID array for. The only practical applications of a RAID array for a non-professional user that I can see are performance for drive-heavy applications and reliability on your data. However, there are better options, in my opinion, for both of these paths.
If you are an avid video editor, like myself, or like to use similarly intensive applications, your hard drive is often the bottleneck. This means that your computer's performance will only be as good as your drive is (presuming you have a good CPU, graphics card and amount of RAM). So, to increase the performance level of your drive, there are several things you can do. You can set up a RAID 0 array, but these (although uncommon) do have a chance to fail, which results in a loss of all your data. Another option is an SSD. Many people have already mentioned this and SSDs are fantastic. They have great read and write speed; the only downside is that they are extremely expensive. Now, a cheaper option is using a SATA III drive and motherboard. SATA III has a maximum speed of 6 gigabits per second, compared to the usual SATA II, which runs at a maximum of 3 gigabits per second. Doubling your drive throughput speed will certainly help. Any of the options here will work; it's just up to you to decide which is best.
Now, as far as data security is concerned, if you would like a RAID array, there is certainly RAID 1, RAID 5 and others, which all provide backup drives to protect your data if one drive fails. The downside to this is that RAID, in general is pretty expensive. Buying two or more identical drives may not be your best option. Instead, you may want to consider purchasing a external hard drive and configuring your computer to automatically back up all of your data. Plus, external drives are portable, which is always a good thing. Also, if you have an old computer laying around, you could set that up as a file server and back up all of your stuff over your network. As you can see, there's plenty of options here as well.
Well I hope I was able to give you some valuable information; let me know if there's anything else you need.
