I can tell you from decades of baking chocolate chip cookies that the brand and variety of the chocolate chip does make a difference in side-by-side tests. In terms of the grocery store name brands, I prefer Hershey's over Nestles.
If you're going to melt them and use them in something like a cake, that might make them a little harder to tell apart, especially if you're also adding cocoa powder.
Milk chocolate chips are very different from semi-sweet chips The dark chocolate chips have a higher percentage of cocoa solids, and usually less sugar.
I stay away from the really cheap house brands, they taste waxy, probably because they scrimp on the actual cocoa products in the chip and use cheaper oils. (Some of the cheap ones can't legally call themselves chocolate.)
The size can make a difference, too. The mini chips seem to almost disappear into the cookie, the big chunk ones will usually become a soft pocket of chocolate in the cookie, hardening a bit over time.
I tend to keep Callabaut couverture callets (semi-sweet and milk chocolate) on hand, but that's because I buy them in large bags. (I'm afraid to find out what an 11 pound bag of them will cost now!)
Valhrona and Scharffenberger are good couverture grade chocolates as well; Guittard and Ghiradelli are OK but I think they're a step down from the couverture grade chocolates.
