so my 80 gb OS Drive is really old. and has become slow. and there is hardly 30GB free from my 500GB HDD. so i know i need to buy something, but am confused between a 1TB WD Blue or 60GB Corsair Sandforce. note: i do a bit of gaming, and a lot of CAD stuff. Also, my motherboard is sata II, and dont have any plans to upgrade in the near future. maybe next year. but i also download a ton of stuff ( ) so i need the space too. so help me make the correct decision.