Can you tell me with CPU you have ? Cause 8GB 1333 is plenty enough for the moment, the most hungry games while playing will never pass the 5Gb of ram. And you must open 30 tabs on internet + a HD vid on background at once to reach 4GB of your system memory.
And a SSD is very fast to navigate true and copy-past and load multiplayer games like BF3/4 and so on.
Take the ssd you will not regret it.