Originally Posted by zahratustra 
if I pick cheaper components (like cheaper GPU)
That is the worst thing you can do. Games are mostly GPU bound not CPU. My 7 year old cpu still plays all the latest games perfectly well. Read the link I gave before. A Core i3-2120 will give almost IDENTICAL performance to a 2500k in games. Meanwhile an extra 50 dollars for the GPU can make 20-30%+ performance difference…
edit: I am pretty sure Gorath didn't mean to cheap out on the GPU as well. If you want to save money reduce the quality of the ram and motherboard and accessories, they make very little difference from a price/performance perspective.