My favorite are the Brett Sherwood cups. They are hand spun/handmade and they just ooze quality and class. I decided to splurge a few years ago after many years of lower end copper and aluminum sets.
The funny thing about it is, while they are very nice to look at and there is some pride of ownership, about a year ago I decided that I would start using coffee cups or mugs for my cups and balls and chop cup routines. My feeling was they are every day objects that can even be borrowed or that are right at hand in a restaurant, bar, peoples' homes, and at most special events. Even though the standard cups and balls with no chop cup in the set aren't gaffed, to a layman they still look like a "magician's prop," and many laymen are suspicious of them. Like Erdnase said, "They should not even suspect, let alone detect." If they believe that a prop or gimmick is responsible for the effect(s), even if that is not the case, it greatly weakens the trick and can even destroy the illusion in their minds.
These days, I mainly do a one cup routine with a coffee cup or mug (borrowed if possible), use olives, grapes, cherries or balled up borrowed dollar bills for the balls (instead of the little odd-looking "sweater balls" I used to use), and a table knife or sharpie serves nicely for when I want a "wand." This gives a very impromptu look and feel.
I have found that the effects that are done with a standard gimmicked chop cup can be duplicated by sleight of hand, and when 3 lemons (or other fruits) are produced out of the ordinary cup for the finale, the reaction is even far greater than it used to be when I used a chop cup.