What would I do? That's easy. Unless the money is really tight, I'd opt for the AI or AIS lenses every time. While the non-AI lenses can be had for less, and will certainly be as good as anything you have for the Minolta, they will severely limit your choice of bodies. Some will be compatible with limited functionality with later bodies, while others will not accept early non-AI lenses at all. With AI or AIS lenses, you don't have that problem and most of them (anything except the "E" series lenses) will have the fork necessary to engage the metering lever on your Nikomat. Some of the AF and AE bodies may not meter with them, but these are only a few.