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That depends, of course, on what the use is and whether the scope has tracking. If the scope has tracking and the purpose is primarily planetary observing, simple eyepieces like Plossls, orthoscopics, and the Takahashi LEs will do just fine.
If, on the other had, the scope does not have tracking, and you are watching the target drift across the field, the highest priority is a coma corrector since the image in a non-corrected newtonian of f/5 or faster is only free from coma in the central millimeter or two in the very center and has compromised images everywhere outside of that. Even Plossls are made sharper everywhere in the field by the use of a coma corrector.
After that, if star clusters and larger objects are being viewed, the a widefield design without astigmatism in the outer field becomes relatively important, and brands like TeleVue and Pentax come to the front, for consideration. Explore Scientific even has a few that meet this requirement, notably the new 92° series and 120° series.
Note that many well-corrected longer focal length eyepieces can be heavy--from 500 to 1300 grams. If the scope is large, this poses no consequential problem, but if the scope is small, say 8-12", then balance becomes a priority (and the ability to add and subtract counterweights), as well has having a strong focuser.
My own taste runs to 100°+ in DSO eyepieces, but that is because of the focal length in my primary scope. In my short focal length apo refractor, I can achieve nice wide fields with eyepieces of narrower field, and I'm enjoying immensely eyepieces like the TeleVue Delites and others of similar field.
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