Is there a ratio as to how much % of free space ssd should have before we hit speed performance? I need 30gb disk for my OS & I plan to buy 60gb corsair.An SSD performs better if it has some empty space on it. Consider buying a 128 GB drive at least. The price difference isn't too much these days. And as suggested above, get Crucial M4/OCZ Vertex 4/Samsung 830, as these are some of the best drives in the market.
The waiting game would never end, it has already become cheaper, 2 yrs ago the same disk were costing 2 times the price that too with old technology.wait for sometime then it will become cheaper...