Thank you for responding.
I need 7 cameras. Would like to have images that are 720p.
Would like to buy from Costco as their warranty policy is beyond compare. However, I recognize that this introduces limits. The limits may or may not be acceptable to me once I know more about advantages and disadvantages of various systems. I do not need to read a license plate from space and I am not planning to create a theatrical release with footage, but I respect and appreciate quality. (I build my own computers for the reason that you allude to in your example).
Have a spare PC that I would like to use as the central base unit (obviously it would need a card of some kind--is this even possible? Is it advisable?).
Think that I would prefer for the wiring to be Ethernet cable rather than coax. Partly because a I have some already and partly because it seems like a system that is Ethernet based is more flexible/useful. Probably should also research whether a wifi solution is possible / advisable (although it seems a tiny bit weird to use security and wifi in the same paragraph).
Would like to stay under $1200, but that is not a hard ceiling (just requires more explaining to my household CFO).
Probably end up doing the install myself. I am not at all opposed to hiring somebody but am very particular about who I have work at my home. I do not currently have anybody in my network that does this kind of work. Can check with friends, but am reluctant to just open the Yellow pages and start calling vendors. And while I understand that some level of expertise is worth paying for, I do not want to overpay for a supposed expert.