What he means by person to person.
You want a?
Hard core gaming pc, or gaming only. Really high power. $800-3000, and up!
A media system. Internet or movies. Less power. $300-$500
Media server. A server for movies and music. Less power. $300-$500
Stand alone server. Mid power. $400-800
Or a gaming pc. High power. $600-$1200
A system for movie making, Or 3d rendering. High power to mid. $600-$2000
Some will need a more powerful cpu, some will need a big hard drive. More than cpu power.
Some will need a combo of hdd, cpu, and video card.
Ram is not really as needed. It helps a lot though. Defiantly on load times. 4 to 8gbs are needed on a gamers rig. While a media server needs about 2gbs.
So what do you want? A normal gaming rig will let you play most games but not maxed out.
While a hard core system will cost more, but well obviously will be faster. The high end will be able to multi task. Meaning you want a cpu capable of running multiple tasks. So like a I7
or I5 if your going intel. A lite pc could use the I3. And get by just fine. But don't expect to run fire fox minecraft and 10 other things at once. Also more isn't always better when buying. You can spend way to much, and be regretting it latter. Make sure to buy what you need. Also.... STAY AWAY FROM DELL OR ALIEN WARE!!!
Most of there systems have built in detection systems in the bios to detect dell hardware.
So replacing old parts can be really expensive. Since you will have to buy the part through them. Not all dells do this. But it isn't worth the costs, risks, or headaches. Trust me.
Also you can say a bit of money going the amd route. Don't listen to the bull crap on the net. Amd are good cpu's so are intel. What matters is which one is on top at that current time. At this time Intel is. But maybe next month it will be amd. Who knows
Now Then what do you want?