You know all those DirectX distribution packages that are "step 1" when you install games? Well, they're all still there on your HDD (or SSD). There's a cool tool that will easily remove those packages with 1 click. I freed up about 1.5GB on my SSD by doing this.
http://www.destructoid.com/a-handy-tip-to-clear-up-hdd-space-if-you-use-steam-a-lot-268934.phtml
http://www.destructoid.com/a-handy-tip-to-clear-up-hdd-space-if-you-use-steam-a-lot-268934.phtml