The upsides to SSD over HDD in gaming more or less relate directly to the game itself. For example, in WoW the way that the code is written you load textures "on the fly". Meaning that whenever you come into a heavily populated area (city), the HD willl struggled to load the textures for display on the video card. You could have a top of the line video card and a ton of memory and it won't make the slightest difference. The SSD HD because of it's read/write speed will naturally display this A LOT quicker.
You will also notice drastically faster load times for just about any other game that has a loading screen. If you play BF3 you won't notice a huge difference because the entire map is loaded when entering the game, hence the long wait times for the level to load. You MAY see a very slight increase with that wait time though.
Games that stream textures from the HD (just about every game now) you will see a noticeable increase. Next to adding more memory to a PC, this is the #1 upgrade I recommend for people, hands down!
Last but not least, don't put too much weight on WEI scores, they don't give a true picture of what your PC can do. I would recommend using some well known bench mark utilities out on the market to really see how your PC holds up.