Sounds like you need a SSD to boot windows and WoW off of for quick loading times I would advise go with the M4 Crucial, but then I would also advise a new computer completely
I would love to build a new computer but with as my computer works as is, I would just like to speed it up. I did some research on the Crucial 128g ssd. they have impressive reviews and it looks as though I will be going this root. Now I just need to research how to swap this stuff over with using a new OS but getting rid of my old one but still keeping the stuff on that HD relevant and available to access.