No you dont, with the set up your looking at you are probably best putting Windows on the SSD and the main programs you use and then put the other stuff onto the normal harddrive.
You could use the SSD as a cashe drive, this is when you partition the SSD and use part of it to cache files for the main harddrive making every thing work quicker.
Raid is where you have more than one drive workign together, its usual to have drives of the same size and speed.
There are various raid levels but the more common are ...
Raid 0, this is where you have 2 or more drives spanning their data between them selves, its also called striped volume, if you have 2 drives that are 1gb each in raid 0 it will class the 2 1gb drives as 1 2gb drive sending some data to each of the drive in theory doubling the speed but if one drive goes down you have lost all your data.
Raid 1, this writes the exact same data to each drive but if you had 2 1gb drives it would show up as just 1 1gb drive, this is so you always have a back up of the data if a drive fails.
Raid 5, this uses a minimum of 3 hard drives, 2 will work together simlar to raid 1 so you get the speed but the 3rd hard drive is a parity drive that basicly backs the data up incase one drive fails.
In raid 5 if you had 3 1gb hard drives it would show up as 1 2gb drive and the 3rd wouldnt be seen.
There are others, google to find out more.
All you need to do is make sure the controler in bios is set to AHCI instead of IDE for the SSD to work properly.