Thanks. Dug out the box it came in, the power supply is 500W, so should be good for what I'm looking for. The 1060 is probably at the upper end of what I'm willing to put into this machine. Is there much difference between the different manufacturers (Zotac, MSI, EVGA, etc.)?
What is the rating of your current PSU? This will influence the over all amount of power actually reaching your hardware. There's a few questions that need to be asked before any recommendations can be made:
1/ What's your budget?
2/ What are you looking to play?
3/ What sort of HDD are you using?
4/ What resolution and refresh is your monitor able to produce?
Performance wise, the two largest QoL improvements that can be made to any gaming machine are an SSD and the GPU. The SSD will reduce loading times significantly, the GPU will give you higher FPS and better graphical fidelity. SSDs are fairly cheap now, GPUs not so much, but a good one can be had on a budget.