The easiest upgrade will be a smaller SSD, you won't need more then 30GB.
I went with a Patriot Torqx 64 GB SSD, which was the smallest in its line.
220mb/sec sequential reads, and a 10 year warranty was a good selling point.
It has the wiper.exe utility (if you're running Win7) which is the same thing as TRIM.

I had to format mine, before it was accessible to add/copy warcraft to it.
I could see it in Device Manager, but not My Computer.

If your motherboard supports AHCI drivers or has them installed already, that is a boost for the speed of an SSD.
Pretty much, change to AHCI in Bios, if you start up you have them.
If you don't, then start in safe mode, and use the disc that came with the motherboard to install them.

There are some tricks to increasing the performance of an SSD.
Things like disabling Indexing on that drive.
If your OS is on the drive too, disable System Restore.
Quite a few tricks actually, a forum search on any site for SSD's will have them.

You won't need a RAID for an SSD.
Basically stick wow on the SSD, or even just the Cache and Data folders and use Symbolic Links to connect this to your normal wow folder. I stuck my whole wow folder on mine, its easier that way.

We don't really get any benefit from putting IS Boxer on the SSD; it runs once and then is in memory until you exit out of it.