Pick a certain year that interests you. I got an old dell dimension e510 prebuilt from 2005, so i decided i want all the core components to be from 2005 (gpu, cpu, case and motherboard). I put a Nvidia Quadro fx 3450 in the pc - i got it free from work from our bin of parts we are sending to recycling, but it IS from 2005. I did max out the motherboard with 4 GB of Corsair DDR2 ram. I chose a cheap Western Digital 150 GB ssd. Just because im too impatient to wait for loading. And for right now I'm keeping the stock motherboard with a pentium 4 3.0 ghz. Dell was doing a weird btx motherboard at the time so upgrade options are limited, cant use an atx mobo in the case. Core 2 duo pcs a lot of people recommend and are cheap, however i feel like those are too new, not 2005 and more of a Windows Vista Cpu. So if anything I'll probably go with an amd motherboard, get like an athlon x2 or something dual core. The pentium 4 does okay with games but man everything else kinda sucks. Also if you want a new power supply for the old pc id go with this one: https://www.amazon.com/dp/B09B8PT4WN?ref=ppx_pop_mob_ap_share Its a 500 watt but it has a lot of older connectors you may not find on newer power supplies, is cheap enough and works great for me. Overall I'm liking my pc but will do more in the future