Well obviously if you want to, but I would strongly strongly urge you don't lose the SSD, and so would everyone else. Having a SSD boosts boot times dramatically and I guess overall computer speed. Downgrade to a 500GB Hard Drive instead of 1TB.
I can suggest something For you but the Corsair Carbide 200r Case really is your best bet. At $50 For a case in it's category you really can't get much cheaper or better. And I wouldn't recommend you went with a cheap case.
One thing I'd also strongly urge you don't downgrade on is the Power Supply, as a great man once said "One thing you don't want to skimp on is the PSU" o: But yeah. You could downgrade to an Intel Core i3 3320 CPU which will save you around $60 And although I wouldn't downgrade to a Dual Core From Quad Core myself, but CPU's aren't the most important thing in a computer if you're a gamer. That being said, having a good CPU is obviously always nice. But I recommend going with the Intel i3 3220.
I know everybody likes to have nice Graphics and be able to play whatever they want on good looking quality, and I know that a GPU downgrade isn't the thing to do when you're a gamer, but since you don't play BF3 and Crysis etc your best bet to save money without having to downgrade too many other parts would be the GPU.
The card I'll recommend isn't very popular with certain people on these Forums and I'm not going to say they don't know what they're talking about, no way. But AMD Graphics Cards aren't bad like people on here seem to say. If they were bad, They would be out of business. They just aren't as good as NVIDIA. But AMD are the way to go if you value Bang For Buck more and if you're on a strict budget. I'd say go with a 2GB AMD 7850 which will save you around $50-60.
Or you can even go with a 2GB EVGA 650Ti which will save you around $60-70 From the original build I listed.
So in conclusion. 2GB GeForce GTX 650Ti / 2GB AMD 7850 Instead of GTX 660.
Intel Core i3 3220 Instead of Intel Core i5 3330
If you go with the downgrades I suggested you'll still have a good computer and you'll save yourself $150+
And you could even downgrade to a 6GB RAM instead of 8GB If you really wanted, but that won't save you much at all.
Hope I helped, best of luck with your build.
Feel Free to drop me a PM or reply in a Thread if you need anymore help.